Evolution characteristics of residual stress in metastable Ni-B alloy coatings identified by nanoindentation

Surface & Coatings Technology 305 (2016) 208–214

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Evolution characteristics of residual stress in metastable Ni-B alloy coatings identified by nanoindentation X. Fang a, G. Jin a,⁎, X.F. Cui b,⁎, J.N. Liu a a b

Institute of Surface/Interface Science and Technology, Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, Harbin Engineering University, Harbin 150001, China College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China

a r t i c l e

i n f o

Article history: Received 16 April 2016 Revised 15 August 2016 Accepted in revised form 16 August 2016 Available online 16 August 2016 Keywords: Electro-brush plating Ni-B Metastable state Nanoindentation Residual stress

a b s t r a c t Residual stress has a strong effect on the mechanical performance of coatings. To understand the mechanism of its generation and evolution in metastable alloy coatings, Ni-B alloy coatings with different degrees of crystallinity were prepared on 0.45% carbon steel substrate by an electro-brush plating technique. The amorphous proportion and grain size were investigated by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). With the help of the Lee model and Suresh model, residual stress in metastable state Ni-B alloy coating was determined from the load-displacement curves obtained by nanoindentation. From XRD and TEM results, the deposition was composed of amorphous and nanocrystalline phases, which contained compressive stress in the asplated coatings. The compressive level decreased with the increase of annealing temperature. Compared with the Suresh model, Lee model is more suitable to evaluate residual stress in the metastable state materials. The experimental results also revealed that the compressive residual stress level was directly related to the total area of grain boundary. © 2016 Elsevier B.V. All rights reserved.

1. Introduction As an advanced remanufacturing technology and important way to combine nano-technology and surface engineering, electro-brush plating (EBP) plays an increasingly important role in repairing and strengthening failure parts [1]. However, in the process of EBP, the consequent residual stress cannot be ignored. Guo-an Cheng et al. [2] have studied the influence of residual stress on mechanical properties of TiAlN thin films. They showed that high residual stress can cause decreasing hardness and modulus of TiAlN thin films. The effect of residual stress on the magnetic properties of electrodeposited nanocrystalline alloys was explored by R.D. Noce et al. [3] Their findings show that the magnetic properties such as coercivity, remanence, saturation magnetization and squareness are strongly dependent on residual stress. Hence, it is critical to control internal residual stress and research the evolution characteristics in science and engineering fields. Two aspects to consider for control of residual stress are: intrinsic stress and external factors. Intrinsic stress is produced by lattice mismatch and the difference in thermal expansion coefficients, which are determined by the stability of coatings and substrates. External factors include plating conditions and bath compositions. A.M. El-Sherik et al. [4] studied the internal stress in nanocrystalline Ni coating with different substrates, and the substrate type was found to affect the magnitude

⁎ Corresponding authors. E-mail addresses: [email protected] (G. Jin), [email protected] (X.F. Cui).

http://dx.doi.org/10.1016/j.surfcoat.2016.08.042 0257-8972/© 2016 Elsevier B.V. All rights reserved.

of internal stress. The research of R. Liu et al. [5] shows the different influences of composition, pH, current density, pulse ratio and stress reducers on internal stress. X-ray diffraction (XRD) [6], curvature [7], neutron diffraction [8] and Raman spectrum [9] are traditional measurements to measure residual stress in coatings. However, they all have disadvantages. For example, in XRD technology, the surface depth is limited. Due to different wavelengths and injection depths, various results are obtained. Bragg equation is a prerequisite for application of XRD. However, amorphous materials and nano-materials, which can result in the deformation of diffraction peaks, are not suitable for the ideal Bragg equation. As for nanoindentation, it has excellent displacement, force and spatial resolution. The relationship between displacement and load can be precisely and continuously recorded. Another merit of nanoindentation is that there is no damage to materials, that is, it is close to nondestructive inspection. In recent years, many people have focused on different models that are calculated from nanoindentation technology to measure residual stress of bulk and film materials. Among these models, Suresh model [10] and Lee model [11] are most popular to study residual stress of uniform single phase materials. Some articles show that this measurement can be applied to plasma spraying iron-based coatings [12] and electrodeposited nickel coatings [13], illustrating the possibility of using nanoindentation to test residual stress of coating surfaces. But for metastable state coatings, especially nanocrystalline/amorphous coatings, further study is needed to determine whether residual stress can be determined by nanoindentation.

X. Fang et al. / Surface & Coatings Technology 305 (2016) 208–214

Herein, metastable state Ni-B coatings with different degrees of crystallinity were prepared by electro-brush plating technology. And nanoindentation combined with Suresh and Lee models was used to study residual stress of the coatings and analyze their evolution characteristics. The purpose of this study is to systematically evaluate residual stress in a metastable state coating and build up the relationship between residual stress and crystallinity. The effects of subsequent annealing on the evolution of residual stress were also explored.

209

Table 2 The critical composition of the electrolyte. Composition

Content (g/L)

Function

Nickel sulfate hexa-hydrate Ammonium citrate Ammonium acetate Lauryl sodium sulfate Boric acid Borane-dimethylamine complex

280 50 35 0.1 30 n

Main salt Complexing agent Complexing agent Surfactant Stabilizer Reductant and B source

2. Experimental 1000 nm at room temperature. For reliable measurement, each sample was measured five times.

2.1. Raw materials The 0.45% carbon steel substrate (200 mm × 200 mm × 100 mm) was produced by wire cutting machine, it required pre-treatment before electro-brush plating. The chemical compositions of the substrate material and electrolyte are provided in Tables 1 and 2, respectively, the analytical reagents (AR), were purchased from Aladding Company. The electrolytes were produced with deionized water. 2.2. Electro-brush plating Before being electro-brush plated, the substrates were first mechanically polished with sandpapers from 60# to 800#, then degreased with acetone, and lastly rinsed with deionized water. The above-mentioned pre-treatments were conducted to remove industrial oil, oxides and other impurities from the surface of the substrates, and, finally, to improve adhesion between the substrate and the coating layer. After the pre-treatments, the Ni-B metastable state alloy coatings were manually brushed by using DSD-30-QA brush plating power supply. The operating conditions are summarized in Table 3. As a non-electrical conductive element, B element needs to be deposited on the substrate surface slowly instead of being directly reduced in the electrolyte. The degree of crystallinity of coating is related to B content, which decreases with increasing precipitation rate of metal ions. A relatively high crystalline coating is obtained by limiting the precipitation rate of metal. In this study, the precipitation rate of metal was controlled by electric current density. The electro-brush plating was conducted in the following steps: electrical cleaning (+ 12 V, 60 s) → strong activation (Activator 2, −12 V, 30 s) → weak activation (Activator 3, − 18 V, 30 s) → electro-brush plating (+ 8 V, 5 min) → post-processing. Between each step, the sample was rinsed with distilled water. The thickness of the coating was about 120 nm which measured by step-thickness gauge. 2.3. Characterizations In X-ray Diffraction (XRD), a Cu Kɑ radiation source was used for studying the phase structure and measuring the crystallinity and grain size of electro-brush plating metastable state alloy coating. JADE 6.5 software was applied to identify the peak positions and calculate the full-width at half-maximum (FWHM) and obtain the degree of crystallinity of the coatings according to Eq. (1). The grain sizes were quantified by applying Scherrer Eq. (2) to the (111) peak and the measured XRD grain sizes were verified by extensive Transmission Electron Microscopy (TEM). The residual stress and its evolution in coatings were mainly analyzed by the nanoindentation technique using Nano-Indenter CETRAPex. All samples were measured by a constant displacement of

Table 1 The chemical composition of 0.45% carbon steel. Element C Content

Si

Mn

Cr

Ni

Cu

Fe

0.42–0.50% 0.17–0.37% 0.50–0.80% ≤0.25% ≤0.30% ≤0.25% The rest

δ ¼ KIa =ðIa þ Ib Þ  100%

ð1Þ

Size ¼ 0:98λ=½FW ðSÞ  cosθ

ð2Þ

where δ is the degree of crystallinity, Ia and Ib represent the diffracted intensity of crystal phase and amorphous phase respectively, K is a correction factor, λ is the wavelength of X-ray, FW(S) is FWHM of a Bragg peak, and θ is the Bragg angle. 2.4. Calculation model of residual stress Nanoindentation technology is used to accurately record the changes of load and displacement. The nanoindentation experiment used the Berkovich indenter, and the indenter was a triangular pyramid. The indentation dwell time was 15 s. The load-displacement curves obtained from the nanoindentation experiment determine the ability of elastic deformation and plastic deformation. Elastic modulus (E) and hardness (H) are calculated from the curves combined with O&P method. 2.4.1. Suresh model Suresh model is based on equibiaxial residual stress. It is suitable for both isotropic elastic and plastic materials without the limitation of material size, from bulk materials to film materials. In this project, residual stress is measured by a method with fixed penetration depth, as given by the equations below: σ ¼ HðA0 =A−1Þ

ðtensile residual stressÞ

σ ¼ Hð1−A0 =AÞ= sinθ

ð3Þ

ðcompressive residual stressÞ

ð4Þ

where σ is residual stress, H is hardness of materials, A0 is projected contact area of materials without stress, A is projected contact area materials under stress. 2.4.2. Lee model Lee model is a new method to measure residual stress which is built upon the Suresh model. This model can be applied to many kinds of stress, including biaxial stress, uniaxial stress and pure shear stress. The equation to obtain main stress is: σ x ¼ 3ðP 0 −P 1 Þ=½ð1 þ kÞA1 

ð5Þ

where P0 and P1 are maximum press load without stress and under stress respectively, A1 is projected contact area under stress.

Table 3 The operating conditions. The operating condition

Parameter

pH Temperature Operating time Voltage

6 Room temperature 8 min 5V

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N iB (1 3 0 )

Intensity (a.u.)

Ni (111)

N iB (0 2 1 ) N iB (1 1 0 )

32 34 36 38 40 42 44 46 48 50 52

3#

Ni (200)

Ni (220)

2# 1#

equiaxed crystals show a uniform distribution in the amorphous matrix. The SAED patterns of polycrystalline are also observed, and the average grain size is similar to the measured results from XRD. In the SAED of alloy coating with 3 g/L DMBA, the diffraction rings are intermittent, whereas Fig. 2(c) shows continuous rings. As for the Ni-B alloy coating with 9 g/L DMBA, the critical continuous rings are in a circle with a diameter of 1.3 μm, indicating a number of fine grains with different orientations in the selected area. Therefore, this sample has more grain boundaries than the sample which has 3 g/L DMBA. In contrast, in considering Fig. 2(b), the crystal non-uniformly distributes in the amorphous phase, and its SAED pattern shows some weak diffraction spots, associated with an area with a small gathering of crystals and fewer crystal boundaries. 3.2. Analysis of load-displacement curves from nanoindentation

28 32 36 40 44 48 52 56 60 64 68 72 76 80 84

2θ(°) Fig. 1. The XRD pattern of the electro-brush plating Ni-B alloy coatings.

In this study, both Suresh model and Lee model were used to calculate equibiaxial stress to explore which model is more suitable for calculating residual stress in metastable coatings. 3. Results and discussion 3.1. Initial as-plated microstructure To obtain different crystallinities, 3 g, 5 g and 9 g Dimethylamine boranes (DMAB) were added into the system to prepare Ni-B alloy coatings. Fig. 1 shows the XRD pattern of Ni-B alloy coatings. Diffraction peaks clearly broaden, which illustrates that electro-brush plating Ni-B coating combines amorphous and nanocrystalline phases. From Eqs. (1) and (2), the values of crystallinity and grain size of the coatings are determined and summarized in Table 4. From Table 4, with an increasing concentration of DMAB, the crystallinity of the coatings decreases because the metalloid element borane facilitates the formation of amorphous phase. However, with continued increase of concentration, crystallinity reduces to a constant value, as a result of distribution of borane in the vicinity of the substrate surface reaching saturation; that is, there is a limited content of borane in the Ni-B alloy coating. In Fig. 1, each sample has an obvious diffraction peak for Ni. The face-centered cubic structure of Ni cannot be changed by borane due to the small deposit rate of borane. In the enlarged view in the right corner of Fig. 1, when 2θ is in the ranges of 32.5° to 33°, 38.5° to 39° and 48° to 48.5°, three strong diffraction peaks of NiB, (110), (021) and (130), are obtained. Therefore, Ni-B coating is a solid solution with B atoms dissolved in Ni substrate. The bright-field TEM image and the corresponding selected area electron diffraction (SAED) pattern of the as-plated Ni-B alloy coating prepared by electro-brush plating are shown in Fig. 2. The SAED pattern of each sample includes a centered diffuse spot and several diffraction rings, which proves that the microstructure of electro-brush plating Ni-B coating is a mixture of crystals (face-centered cubic structure) and amorphous phases. There evenly distributed small size grains and the grain boundary were obvious. From Fig. 2(a) and (c), many Table 4 The crystallinity and grain size of the electro-brush plating Ni-B alloy coatings. Content of DMAB (g/L) in electrolyte

Crystallinity (%)

Grain size (nm)

3 5 9

42.36 33.52 32.59

13.86 18.44 12.29

The load-displacement curves of electro-brush plating Ni-B alloy coatings, shown in Fig. 3, are similar to the typical load-displacement curve of a soft metal. Significant elastic recovery, which is observed in Fig. 3, is used to distinguish samples with residual stress from others without residual stress. With the platform at maximum load, the displacement still increases due to creep [14]. As shown in Fig. 3, the maximum loads of three samples are higher than those of their control samples, suggesting that compressive residual stress exists in the as-plated Ni-B alloy coating, since tensile stress promotes the depth of indentation whereas compressive stress reduces the depth. From Fig. 3(a), two intersecting points are evident, and the slope of the curve of the coating with residual stress is larger than that of the other one, illustrating that parts of the microstructure in this sample are uneven. 3.3. Calculation of residual stress Oliver-Pharr Method [15] is used to calculate projected area of indentation; the residual stress of metastable Ni-B alloy coatings is obtained by Suresh model and Lee model. The results are shown in Table 5. From Fig. 3 and the analysis method mentioned above, residual stresses of the coatings with 3 g/L and 5 g/L DMBA are compressive and their values are negative. In Table 5, the results from Suresh model are opposite to that from Fig. 3. The coating is multiple crystal structure. In the process of indentation, the residual deformation is different in the homogeneous regions and the phase interface. The influence to the hardness from the residual stress is ignored in the Suresh model. So the area parameter A which used in the stress calculation is not accurate. However, the area parameter isn't needed in the calculation of Lee model. So L model is more suitable. Therefore, Lee model is more suitable for metastable alloy coatings with uneven microstructure than Suresh model to calculate residual stress. With regard to the Lee model, the maximum load is directly observed, which plays a key role in the calculation of residual stress. Errors which are caused by the indentation projected area and the non-uniform microstructure related hardness can be avoided. As known, residual tensile stress cannot only enhance the bonding strength between coating and substrate, but also prevent fatigue cracks from extending [16]. As for the samples with 5 g/L and 9 g/L DMBA, their crystallinities are similar, but the grains in the coating with lower content of DMBA are larger than those of the other coating. The larger grains result in the smaller total grain boundary areas, and an uneven microstructure in the 5 g/L DMBA coating leads to a decrease of the residual compressive stress level. A previous study suggested that the internal stress of amorphous alloy was lower than that of normal crystalline due to no visible grain boundary in the amorphous alloy, resulting in the distortion of lattice. According to this conclusion, the residual stress of the specimen with 5 g/L DMBA should be smaller than that of the specimen with 3 g/L DMBA because of the lower degree of crystallinity. But the experimental results are contrary to the existing theory. Hence,

X. Fang et al. / Surface & Coatings Technology 305 (2016) 208–214

(a)

(c)

(b)

100nm

50 nm

100nm

211

Fig. 2. Bright-field image and the corresponding selected area electron diffraction pattern of Ni-B alloy coatings. (a) the coating with 3 g/L DMBA; (b) the coating with 5 g/L DMBA; (c) the coating with 9 g/L DMBA.

burst or overflow from the coating surface, leading to lattice contraction and local tensile stress. The smaller grain size causes stronger hydrogen evolution and consequent heavy lattice contraction as well as larger tensile stress. Thirdly, high energy is obtained at the grain boundary. Unbalanced crystallization occurs during electro-brush plating. Therefore many defects like voids gather around grain boundaries which result in excessive free volumes. Large grain areas mean more free volumes [17]. On the one hand, free volumes can prevent dislocation from slipping. Then a large distortion appears and residual stress increases. On the other hand, the disappearance of free volumes induces the contraction of grain boundaries and tensile stress improves. So in this study, the important factor affecting the evolution of internal residual stress in metastable coatings is the competition between inherent compressive stress and tensile stress due to lattice distortion. With enhancing degree of lattice distortion caused by grain refinement, residual stress of coatings varies from compressive stress to unstressed state and finally, to tensile stress.

it is necessary to differentiate crystalline/amorphous hybrid microstructure from pure amorphous structure. In this project, when amorphous/nanocrystalline hybrid microstructure is considered, the critical factor that affects value and properties of residual stress is the total area of grain boundaries. A large total area leads to serious lattice mismatch, so higher residual stress is obtained. According to the theory, that grain size and total area of grain boundaries are in inverse ratio, the enhancing sequence of grain boundary area is the sample with 5 g/L, 3 g/L and 9 g/L DMBA. With an increase in total area of grain boundaries, the internal stress of coatings evolves from residual compressive stress to residual tensile stress. Reasons to explain this are: first, Ni-B alloy has a face-centered cubic structure and the lattice parameter is 0.353 nm. 0.45% carbon steel has body-centered cubic structure and the lattice parameter is 0.286 nm. Due to their different lattice parameters, the intrinsic stress in the coatings is compressive. Secondly, during electro-brush plating, bubbles produced in the hydrogen evolution process are on the coating surface. These can 60

(a) Residual stress Stress-free

30 20 10

65.975

Residual stress Stress-free

60

40

77.519

(b)

70

45.058

Load (mN)

Load (mN)

50

80

56.466

50 40 30 20 10 0

0 0

200

400

600

800

1000

1200

-10

0

Displacement (nm) 100

400

600

800

1000

Displacement (nm)

(c)

100.099 92.996 Residual stress Stress-free

80

Load (mN)

200

60 40 20 0 0

200

400

600

800

1000

Displacement (nm) Fig. 3. The load-displacement curves of electro-brush plating Ni-B alloy coatings. (a) the coating with 3 g/L DMBA; (b) the coating with 5 g/L DMBA; (c) the coating with 9 g/L DMBA.

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3.4. Effect of annealing temperature on residual stress

Table 5 Residual stress of metastable Ni-B alloy coatings. Content of DMAB in the electrolyte (g/L)

A0/A

hf/hmax

σ/GPa

σx/GPa

3 5 9

0.688 0.773 0.734

0.676 0.799 0.628

3.979 3.130 −0.328

−0.964 −1.164 −0.782

A0: the indentation projected area of the sample without stress. A: the indentation projected area of the sample under stress. σ: residual stress calculated by Suresh model. σx: residual stress calculated by Lee model.

100

(a)

85.631

Reesiduaal streess Strress-fr free

100

719 68.7

60 40 20

(b)

96 6.771

85.6 686

Ressiduall stresss Streess-frree

80

Load (mN)

Load (mN)

80

To explore evolution features of residual stress in metastable Ni-B alloy coatings in the process of heat treatments, seven Ni-B alloy coatings were respectively put under heat preservation at 205 °C, 255 °C, 305 °C, 355 °C, 405 °C, 500 °C and 600 °C for an hour, followed by air cooling. Fig. 4 illustrates their load-displacement curves from nanoindentation. The maximum indentation load of the sample with stress is higher than that of the stress free sample. This means that, after heat treatment, residual compressive stress still exists in the Ni-B alloy

60 40 20

0

0

0

200

4 400

6000

800

1000

120 00

0

Displaccemeent (nnm)

200

400 4

6000

800

10000

120 00

D placeemennt (nnm) Disp

(c)

(d)

(e)

(f)

(g)

(h)

Fig. 4. The load-displacement curves of Ni-B alloy coatings with 5 g/L DMBA under different heat treatments. (a) as-plated; (b) 205 °C; (c) 255 °C; (d) 305 °C; (e) 355 °C; (f) 405 °C; (g) 500 °C; (h) 600 °C.

X. Fang et al. / Surface & Coatings Technology 305 (2016) 208–214

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coating, which is the same with the initial residual stress in the original as-plated coating. The load-displacement curve of the initial as-plated coating is clarified in Fig. 4(a), where the offset graph of the sample with stress occurs below the graph of the stress free sample (the area shown by arrow head). This is because the internal microstructure in the original as-plated coating is partly non-uniform. However, when Ni-B alloy coating undergoes thermal treatment, its curve shows the representative load-displacement curve of nanoindentation. Hence, heat treatment obviously improves the uniformity of coating microstructure. According to the calculated result from Lee model, the evolution of residual stress after heat treatment in Ni-B alloy coating with 5 g/L DMBA is determined (Fig. 5). The initial compressive stress in the coating decreases when heat temperature rises, due to the competition between the tensile stress resulting from contraction of the total volume of coating and the original compressive stress. During the process of heat treatment, the critical reasons why the coating volume shrinks include phase change, vacancy, dislocation, disappearance of grain boundary and precipitation of solid solution. First, after the amorphous part of the amorphous/nanocrystalline coating crystallizes, the density enhances by 1%–2%. So volume contraction appears [18] and the value of tensile stress improves. Secondly, under high temperature, atomic diffusion on the interface between 0.45% carbon steel and Ni-B coating, and in the coating, results in the disappearance of excessive free volumes such as micropores and vacancies. If a vacancy in the crystal moves to a grain boundary and disappears due to thermal energy from the outside environment, the crystal volume reduces as well as the compressive stress in the original coating. At the same time, the disappearance dislocation in the crystal reduces microstrain [19] and stress relaxation occurs. Thirdly, nanocrystals grow up in the process of heating, leading to an increase of tensile stress. On the one hand, in the crystal, the density of grain boundary is lower than that inside the crystal. Therefore, the growth of crystal causes an improved density of the coating and finally a reduction of total coating volume. On the other hand, the interatomic force gradually increases with decreasing distance between atoms [20]. But the enhancing tensile stress offsets the original compressive stress because of the limitation of 0.45% carbon steel. Fourthly, solid solution Ni(B) precipitates from Ni-B alloy coating and segregates at the grain boundary, resulting in the separation of grain boundaries and improvement of the grain boundary area.

The crystallinity and grain size of coatings were calculated by XRD diffraction curves. Based on the principle of nanoindentation, Suresh model and Lee model were used to measure residual stress of the coatings and verify which model is more suitable for Ni-B alloy coatings. We found the following.

4. Conclusions

References

In this project, different contents of DMBA were added into the plating solution and Ni-B alloy coatings of various crystallinities prepared.

1.739

σ- (Gpa)

1.4

Residual stress value Fitting line 1.251 1.137

0.7

0.553 0.464 0.356

0.379 0.140

0.0

0

200

400

T (°C)

600

Fig. 5. Evolution of residual stress under heat treatment in Ni-B alloy coating with 5 g/L DMBA.

(1) The XRD and TEM results indicate that the electro-brush plating Ni-B alloy coating is composed of crystalline and amorphous phases. The percent of amorphous microstructure enhances with increasing content of Borane until it reaches saturation. And Ni-B alloy coating mainly contains Ni element and Ni(B) solid solution. (2) It is more accurate to calculate residual stress of uneven microstructure by Lee model than Suresh model. (3) The as-plated Ni-B alloy coating has residual compressive stress and its value and properties are related to crystallinity and grain size. The residual compressive stress reduces with an increasing total area of grain boundary and decreasing grain size, therefore, it is reasonable to control residual stress level by control of grain size and crystallinity. (4) During the process of heat treatment, disappearance of defects such as vacancy, amorphous crystallization and the growth of crystal result in the contraction of coating volume and improvement of microstructure density. Consequently, internal tensile stress increases and counteracts the initially residual compressive stress. But tensile stress caused by microstructure change is always lower than the initial compressive stress. Therefore, the overall compressive stress reduces.

Acknowledgement This work was financially supported by the National Basic Research Program of China (973 Program) (No. 2011CB013404, 61328303), National Natural Science Foundation of China (No. 51275105, 21275037, 51375106), China Postdoctoral Science Foundation (No. 2015M571390), Hei Long Jiang Postdoctoral Foundation (No. LBHZ14050), Special Foundation for Harbin Science and Technology Innovation (No. 2015RAXXJ016), Fundamental Research Funds for the Central Universities (No. HEUCF20161013, 20161017).

[1] Shi Peijing, Wang Hongmei, Zhang Wei, Xu Binshi, Advanced Automatic Remanufacturing Technology, 2013 Fifth Conference on Measuring Technology and Mechatronics Automation (2013) 156–158. [2] G.-a. Cheng, D.-y. Han, C.-l. Liang, X.-l. Wu, R.-t. Zheng, Influence of residual stress on mechanical properties of TiAlN thin films, Surf. Coat. Technol. 228 (2013) S328–S330. [3] R.D. Noce, N. Barelli, R.F.C. Marques, P.T.A. Sumodjo, A.V. Benedetti, The influence of residual stress and crystallite size on the magnetic properties of electrodeposited nanocrystalline Pd-Co alloys, Surf. Coat. Technol. 202 (2007) 107–113. [4] A.M. El-Sherik, J. Shirokoff, U. Erb, Stress measurements in nanocrystalline Ni electrodeposits, J. Alloys Compd. 389 (2005) 140–143. [5] R. Liu, H. Wang, X.-P. Li, G.-F. Ding, Study of internal stress of amorphous Ni-W alloy films, Mater. Sci. Technol. 25 (8) (2009) 960–968. [6] M. Gelfi, E. Bontempi, R. Roberti, et al., Residual stress analysis of thin films and coatings through XRD experiments[J], Thin Solid Films 450 (1) (2004) 143–147. [7] R. Liu, H. Wang, X.P. Li, et al., Study of internal stress of amorphous Ni–W alloy films[J], Mater. Sci. Technol. 25 (8) (2009) 960–968. [8] H. Alipooramirabad, A. Paradowska, R. Ghomashchi, et al., Quantification of residual stresses in multi-pass welds using neutron diffraction[J], J. Mater. Process. Technol. 226 (2015) 40–49. [9] S. Kouteva-arguirova, W. Seifert, M. Kittler, J. Relf, Rama measurement of stress distribution in multicrystalline silicon materials[J], Mater. Sci. Eng. B 102 (2003) 37–42. [10] S. Suresh, A.E. Giannakopoulos, A new method for estimating residual stresses by instrumented sharp indentation[J], Acta Mater. 46 (16) (1998) 5755–5767. [11] Y.H. Lee, D. Kwon, Measurement of residual-stress effect by nanoindentation on elastically strained (100) W[J], Scr. Mater. 49 (5) (2003) 459–465. [12] W. Haidou, Z. Lina, X. Binshi, Measurement of residual stress of plasma sprayed Febased coating by nanoindentation[J], J. Mech. Eng. 49 (7) (2013) 1–4. [13] Z. Sha, Z. Yichun, Measurement study of residual stress in electrodeposited nickel coating by instrument nanoindentation[J], Mater. Rev. 22 (2) (2008) 115–118.

214

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[14] D. Beegan, S. Chowdhury, M.T. Laugier, A nanoindentation study of copper films on oxidised silicon substrates[J], Surf. Coat. Technol. 176 (1) (2003) 124–130. [15] I.N. Sneddon, The relation between load and penetration in the axisymmetric Boussinesq problem for a punch of arbitrary profile[J], Int. J. Eng. Sci. 3 (1) (1965) 47–57. [16] A.A. Solov'ev, N.S. Sochugov, K.V. Oskomov, Effect of residual internal stresses in tin coatings on specific losses in anisotropic electrical steel[J], Phys. Met. Metallogr. 109 (2) (2010) 111–119.

[17] T.D. Ziebell, C.A. Schuh, Residual stress in electrodeposited nanocrystalline nickeltungsten coatings[J], J. Mater. Res. 27 (09) (2012) 1271–1284. [18] L.A. Davis, Metallic Glasses[M]//Fundamental Aspects of Structural Alloy Design, Springer, US, 1977 431–450. [19] L.H. Qian, S.C. Wang, Y.H. Zhao, et al., Microstrain effect on thermal properties of nanocrystalline Cu[J], Acta Mater. 50 (13) (2002) 3425–3434. [20] P. Chaudhari, Grain growth and stress relief in thin films[J], J. Vac. Sci. Technol. 9 (1) (1972) 520–522.