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Research on friction and wear behavior of a bulk metallic glass under different sliding velocity
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Research on friction and wear behavior of a bulk metallic glass under different sliding velocity Pingjun Tao n, Yuanzheng Yang, Zhiwei Xie, Yuding He School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
art ic l e i nf o
a b s t r a c t
Article history: Received 21 February 2015 Accepted 15 March 2015
Linear reciprocating sliding friction and wear behaviors in a Zr55Cu30Ni5Al10 bulk metallic glass (BMG) at different sliding velocities were investigated. The friction and wear tests nearly have not changed the amorphous structure and thermal stability of the BMG. The sliding velocity significantly affects the friction and wear behaviors of the BMG. During the frictional and wear tests, the average frictional coefficient locates between 0.244 and 0.302 and increases gradually with increasing sliding velocity. The grinding trace width locates between 36 μm and 227 μm and descends gradually with increasing sliding velocity. The grinding traces exhibit smooth linear furrows, on both sides of which some heaping alloy scraps can be observed, while at the ends of which these accumulation extent of surface alloy scraps becomes more serious. The smaller the sliding velocity is, the more serious the wear extent is. At smaller sliding velocities, the wear mechanism inclines to the combined effects of continuous wear, occlusion or bite welding, adhesive wear and abrasive wear. With the increase of sliding velocity, the wear mechanism changes gradually to a combined result of slight bite or bite welding and continuous wear. & 2015 Published by Elsevier B.V.
Keywords: Amorphous materials Metals and alloys Solidification Wear and tribology
1. Introduction Bulk metallic glasses (BMGs) have attracted considerable attentions because of their potential applications as structure materials [1]. BMGs usually show high strength, large elastic strain limit, excellent corrosion resistances and other remarkable engineering properties [2–5]. Today, several families of multi-component BMGs have been developed by scientific researchers, among which Zr-based BMGs are of particular interest and have been utilized commercially to produce items such as sporting goods and electronic castings [6,7]. Although considerable works have been done on these alloys and some new multi-component BMGs have been discovered with promising properties, still more efforts are required to do for us to comprehensively understand and master these new alloys. The tribological properties must be taken into account in some engineering applications [8,9]. For example, amorphous alloys have been proposed as coatings in dry bearing in space, and the viscous flow of amorphous alloys has been exploited to manufacture mechanical devices such as ultra-fine gear. In these applications, the frictional and wear properties are of direct concern [5,10]. Several studies have reported that metallic glasses exhibit promising tribological and wear-resistant properties. However, there are few literatures about linear reciprocating n
Corresponding author. Tel./fax: þ 86 20 39322570. E-mail address: [email protected] (P. Tao).
sliding friction and wear behaviors of amorphous alloys. In addition, whether the friction and wear experiments would affect the structure and thermal stability of amorphous alloys is not very clear. In present paper, linear reciprocating sliding friction and wear behaviors in a Zr55Cu30Ni5Al10 BMG at different sliding velocities were investigated. Through above researches, the corresponding mechanism of frictional and wear can be obtain, meanwhile, it’s expected that the relative theoretical foundation for engineering applications of BMGs should be established.
2. Experimental procedures A master alloy with a nominal composition of Zr55Cu30Ni5Al10 (numbers indicate at%) has been prepared in a Ti-gettered argon atmosphere. A plate-like alloy sample was fabricated by casting the liquid master alloy into a copper mould with a cavity of 1 10 70 mm3. After the amorphous nature has been confirmed, the as-cast BMG alloy plate was cut into small specimens with a dimension of 1 10 10 mm3. The specimens cut out were ground and polished to an exact desired finish for the sake of friction and wear tests. The room temperature surface dry linear reciprocating sliding friction and wear tests were carried out on a LKDM-2000 minitype friction and wear testing apparatus using quenched GCr15 steel balls with a diameter of 3 mm under a normal load of 3 N (P¼ 3 N). The sliding velocity (Vs) ranges from
http://dx.doi.org/10.1016/j.matlet.2015.03.075 0167-577X/& 2015 Published by Elsevier B.V.
Please cite this article as: Tao P, et al. Research on friction and wear behavior of a bulk metallic glass under different sliding velocity. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2015.03.075i
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
P. Tao et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
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Fig. 2. (A) Relation between fc and Nrs with Vs ranging from 50 to 250 mm/min and (B) relationships among fca, Vs and Rf.
Fig. 1. (A) XRD patterns of the alloys after tests with different Vss and (B) DSC curve of the as-cast alloy and that of a specimen test at 250 mm/min.
50 to 250 mm/min, meanwhile, the sliding length (Ls) and the number of linear reciprocating sliding (Nrs) were fixed to 3 mm and 50, respectively. Each GCr15 steel ball was used only one time. After the tests, the specimens were then cleaned with ethanol in a supersonic cleaner before observation of the worn surfaces by using an S-3400N Scanning Electron Microscopy (SEM).
3. Results and discussion Fig. 1A shows the XRD patterns of the specimens after the friction and wear tests with different Vs. It can be seen that the XRD patterns exhibit only one diffuse peak without any evidence of crystalline phase, again indicating the characteristic of the amorphous structure. Fig. 1B shows the DSC curve of the as-cast BMG sample. As a comparison, the DSC curve of one specimen after the friction and wear test at Vs of 250 mm/min is also presented. Both specimens exhibit one endothermic event, characteristic of the glass transition, followed by an exothermic event due to crystallization processes. The crystallization temperature (Tx) and crystallization peak temperature (Tp) of the as-cast sample is about 481 and 493 K, respectively, while, Tx and Tp of the sample tested at Vs of 250 mm/min is very close to the responding thermal
parameter of the former, respectively. The above results demonstrate that the friction and wear tests nearly have not changed the structure and thermal stability of the BMG. The frictional coefficient (fc) as a function of Nrs at different sliding velocities is shown in Fig. 2A. It can be seen that for a certain sliding velocity, with the increase of Nrs, the range of frictional coefficient presents an upward trend, i.e., the frictional coefficient increases gradually. However, the fluctuation range of frictional coefficient changes little and the corresponding frictional coefficient grows slowly, indicating that the anti-friction properties of the BMG have a very good stability. With the increase of sliding velocity, the fluctuation range of frictional coefficient exhibits a gradual increasing trend, showing the corresponding frictional coefficient increases continuously. Overall, the frictional coefficients of the BMG specimens are relative low, mainly locating between 0.18 and 0.404, among which, the maximum fluctuation range is 0.264. Fig. 2B shows the relationships among average fictional coefficient (fca), frictional coefficient range (Rf) and sliding velocity for the BMG specimens. The experiment results obtained under these conditions are summarized in Table 1. It can be found that, during the linear reciprocating sliding motion processes of GCr15 steel balls under a nominal load of 3 N, the maximum frictional coefficient (fcm) of the BMG fluctuates in the range of 0.302– 0.404 and the average frictional coefficient locates between 0.244 and 0.302. With the increase of sliding velocity, the average frictional coefficient increases gradually, while the frictional coefficient range presents an upward trend in a wave style on the whole.
Please cite this article as: Tao P, et al. Research on friction and wear behavior of a bulk metallic glass under different sliding velocity. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2015.03.075i
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132
P. Tao et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
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Table 1 Characteristic parameters of frictional coefficient under P¼ 3 N with different Vss. Nrs
Vs (mm/min)
fcm
Rf
fca
50 50 50 50 50
50 100 150 200 250
0.349 0.302 0.350 0.319 0.444
0.189 0.175 0.215 0.209 0.264
0.244 0.257 0.272 0.276 0.302
3
These can be due to following reasons. At low and moderate sliding velocities, the friction is mainly caused by the local adhesion contact and shearing of contact areas. The frictional resistance produces surface heat, which always has been regarded as a temporary and local phenomenon, resulting in the fusion and aggregation of the broken surface layer alloys. [12]. The grinding trace width (GTW) locates between 36 μm and 227 μm and descends gradually with increasing sliding velocity, as shown in Fig. 3, indicating that the smaller the sliding velocity, the more serious the wear extent, and vice versa. At smaller sliding velocities, the numbers of alloy scrapes are relatively larger and the wear mechanism inclines to the combined effects of continuous wear, occlusion or bite welding, adhesive wear and abrasive wear. With the increase of sliding velocity, the numbers of the alloy scrapes reduce gradually and the wear mechanism changes gradually to a combined result of slight bite or bite welding and continuous wear.
4. Conclusions
Fig. 3. GTW as a function of Vs with P¼ 3 N and Nrs ¼ 50 for the alloys. (A and B) SEM images of middle and end grinding traces with Vs ¼150 mm/min; (C–F) SEM images of grinding traces with Vs ¼ 50, 100, 200 and 250 mm/min, respectively.
SEM morphological images of middle and end grinding traces tested at a sliding velocity of 150 mm/min are shown in insets A and B in Fig. 3. The grinding trace exhibits smooth linear furrows, on both sides of which some heaping alloy scraps can be observed, as seen in inset A, while at the ends of which these accumulation extent of surface alloy scraps becomes more serious and the accumulation surface alloy scraps present a preferred orientation, along the arrow direction shown in inset B. These friction and wear behaviors are in line with the welding, shearing and plowing theory proposed by Bowden [11]. The high pressure between the GCr15 steel ball and the surface of the BMG will bond the contact points. Then during the relative sliding process in the contact surface, partial bonded connection points will be sheared off and cut off. The asperities of the steel ball plowing the surface of the BMG will cause the formation of friction adhesion component, which will shear and plow the surface layer alloy of the BMG continuously. Then the broken surface layer alloy pieces formed will be pushed towards both sides and ends of the grinding trace, leading to the formation of typical surface material transfer phenomena in the process of metal’s friction and wear [12]. Insets C–F show the SEM morphological images of grinding traces tested at Vs ¼50, 100, 200 and 250 mm/min, respectively. Combined with inset B, it can be found that at smaller sliding velocities there are more alloy debrises torn from the contact areas of the bonded surface in the course of sliding processes. While at larger sliding velocities, relatively smaller alloy scrapses can be observed. On both sides of the grinding traces, a gradual increasing surface layer alloy debrises in concentration state to be transferred can be seen.
The sliding velocity significantly affects the friction and wear behaviors of the BMG. During the linear reciprocating sliding friction and wear tests, the average frictional coefficient locates between 0.244 and 0.302 and increases gradually with increasing sliding velocity. The grinding trace width locates between 36 μm and 227 μm and descends gradually with increasing sliding velocity. The grinding traces exhibit smooth linear furrows. The smaller the sliding velocity is, the more serious the wear and tear is. At smaller sliding velocities, the numbers of alloy scrapes in the grinding traces are relatively larger and the wear mechanism inclines to the combined effects of continuous wear, occlusion or bite welding, adhesive wear and abrasive wear. With the increase of sliding velocity, the numbers of the alloy scrapes reduce gradually and the wear mechanism changes gradually to a combined result of slight bite or bite welding and continuous wear.
Acknowledgements This work is supported by the National Natural Science Foundation of China (51201038), the Higher Specialized Research Foundation for Doctoral Program (20124420120009, 20124420110007), the National Natural Science Foundation of Guangdong (S2012040007575), and the CPGPME (2012B091100133, 2012B091100099, 2012B091100303). References [1] Kim J. Mater Lett 2014;130:160–3. [2] Kawashima A, Wada T, Ohmura K, Xie GQ, Inoue A. Mater Sci Eng, A 2012;542:140–6. [3] Wang L, Chao YS. Mater Lett 2012;69:76–8. [4] Zhang SG, Li JG. Mater Lett 2012;75:179–82. [5] Duan HT, Tu JS, Du SM, Kou HC, Li Y, Wang JP, Chen ZW, Li J. Mater Des 2011;32:4573–9. [6] Inoue A, Zhang T, Ishihara S, Saida J, Matsushita M. Scr Mater 2001;44:1615–9. [7] Hishiyama N, Amiya K, Inoue A. J Non-Cryst Solids 2007;353:3615–21. [8] Monnet G, Pouchon MA. Mater Lett 2013;98:128–30. [9] Geringer J, Macdonald DD. Mater Lett 2014;134:152–7. [10] Fleury E, Lee SM, Ahn HS, Kim WT, Kim DH. Mater Sci Eng, A 2007;375-377:276–9. [11] Dowson D, Higginson GR. Elastohydrodynamic lubrication. Oxford: Pergamon; 1966. [12] Moore DF. Principle and applications of tribology. London: Robert Maxwell, MC; 1975.
Please cite this article as: Tao P, et al. Research on friction and wear behavior of a bulk metallic glass under different sliding velocity. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2015.03.075i
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Q1 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Research on friction and wear behavior of a bulk metallic glass under different sliding velocity Pingjun Tao n, Yuanzheng Yang, Zhiwei Xie, Yuding He School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
art ic l e i nf o
a b s t r a c t
Article history: Received 21 February 2015 Accepted 15 March 2015
Linear reciprocating sliding friction and wear behaviors in a Zr55Cu30Ni5Al10 bulk metallic glass (BMG) at different sliding velocities were investigated. The friction and wear tests nearly have not changed the amorphous structure and thermal stability of the BMG. The sliding velocity significantly affects the friction and wear behaviors of the BMG. During the frictional and wear tests, the average frictional coefficient locates between 0.244 and 0.302 and increases gradually with increasing sliding velocity. The grinding trace width locates between 36 μm and 227 μm and descends gradually with increasing sliding velocity. The grinding traces exhibit smooth linear furrows, on both sides of which some heaping alloy scraps can be observed, while at the ends of which these accumulation extent of surface alloy scraps becomes more serious. The smaller the sliding velocity is, the more serious the wear extent is. At smaller sliding velocities, the wear mechanism inclines to the combined effects of continuous wear, occlusion or bite welding, adhesive wear and abrasive wear. With the increase of sliding velocity, the wear mechanism changes gradually to a combined result of slight bite or bite welding and continuous wear. & 2015 Published by Elsevier B.V.
Keywords: Amorphous materials Metals and alloys Solidification Wear and tribology
1. Introduction Bulk metallic glasses (BMGs) have attracted considerable attentions because of their potential applications as structure materials [1]. BMGs usually show high strength, large elastic strain limit, excellent corrosion resistances and other remarkable engineering properties [2–5]. Today, several families of multi-component BMGs have been developed by scientific researchers, among which Zr-based BMGs are of particular interest and have been utilized commercially to produce items such as sporting goods and electronic castings [6,7]. Although considerable works have been done on these alloys and some new multi-component BMGs have been discovered with promising properties, still more efforts are required to do for us to comprehensively understand and master these new alloys. The tribological properties must be taken into account in some engineering applications [8,9]. For example, amorphous alloys have been proposed as coatings in dry bearing in space, and the viscous flow of amorphous alloys has been exploited to manufacture mechanical devices such as ultra-fine gear. In these applications, the frictional and wear properties are of direct concern [5,10]. Several studies have reported that metallic glasses exhibit promising tribological and wear-resistant properties. However, there are few literatures about linear reciprocating n
Corresponding author. Tel./fax: þ 86 20 39322570. E-mail address: [email protected] (P. Tao).
sliding friction and wear behaviors of amorphous alloys. In addition, whether the friction and wear experiments would affect the structure and thermal stability of amorphous alloys is not very clear. In present paper, linear reciprocating sliding friction and wear behaviors in a Zr55Cu30Ni5Al10 BMG at different sliding velocities were investigated. Through above researches, the corresponding mechanism of frictional and wear can be obtain, meanwhile, it’s expected that the relative theoretical foundation for engineering applications of BMGs should be established.
2. Experimental procedures A master alloy with a nominal composition of Zr55Cu30Ni5Al10 (numbers indicate at%) has been prepared in a Ti-gettered argon atmosphere. A plate-like alloy sample was fabricated by casting the liquid master alloy into a copper mould with a cavity of 1 10 70 mm3. After the amorphous nature has been confirmed, the as-cast BMG alloy plate was cut into small specimens with a dimension of 1 10 10 mm3. The specimens cut out were ground and polished to an exact desired finish for the sake of friction and wear tests. The room temperature surface dry linear reciprocating sliding friction and wear tests were carried out on a LKDM-2000 minitype friction and wear testing apparatus using quenched GCr15 steel balls with a diameter of 3 mm under a normal load of 3 N (P¼ 3 N). The sliding velocity (Vs) ranges from
http://dx.doi.org/10.1016/j.matlet.2015.03.075 0167-577X/& 2015 Published by Elsevier B.V.
Please cite this article as: Tao P, et al. Research on friction and wear behavior of a bulk metallic glass under different sliding velocity. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2015.03.075i
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
P. Tao et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
Fig. 2. (A) Relation between fc and Nrs with Vs ranging from 50 to 250 mm/min and (B) relationships among fca, Vs and Rf.
Fig. 1. (A) XRD patterns of the alloys after tests with different Vss and (B) DSC curve of the as-cast alloy and that of a specimen test at 250 mm/min.
50 to 250 mm/min, meanwhile, the sliding length (Ls) and the number of linear reciprocating sliding (Nrs) were fixed to 3 mm and 50, respectively. Each GCr15 steel ball was used only one time. After the tests, the specimens were then cleaned with ethanol in a supersonic cleaner before observation of the worn surfaces by using an S-3400N Scanning Electron Microscopy (SEM).
3. Results and discussion Fig. 1A shows the XRD patterns of the specimens after the friction and wear tests with different Vs. It can be seen that the XRD patterns exhibit only one diffuse peak without any evidence of crystalline phase, again indicating the characteristic of the amorphous structure. Fig. 1B shows the DSC curve of the as-cast BMG sample. As a comparison, the DSC curve of one specimen after the friction and wear test at Vs of 250 mm/min is also presented. Both specimens exhibit one endothermic event, characteristic of the glass transition, followed by an exothermic event due to crystallization processes. The crystallization temperature (Tx) and crystallization peak temperature (Tp) of the as-cast sample is about 481 and 493 K, respectively, while, Tx and Tp of the sample tested at Vs of 250 mm/min is very close to the responding thermal
parameter of the former, respectively. The above results demonstrate that the friction and wear tests nearly have not changed the structure and thermal stability of the BMG. The frictional coefficient (fc) as a function of Nrs at different sliding velocities is shown in Fig. 2A. It can be seen that for a certain sliding velocity, with the increase of Nrs, the range of frictional coefficient presents an upward trend, i.e., the frictional coefficient increases gradually. However, the fluctuation range of frictional coefficient changes little and the corresponding frictional coefficient grows slowly, indicating that the anti-friction properties of the BMG have a very good stability. With the increase of sliding velocity, the fluctuation range of frictional coefficient exhibits a gradual increasing trend, showing the corresponding frictional coefficient increases continuously. Overall, the frictional coefficients of the BMG specimens are relative low, mainly locating between 0.18 and 0.404, among which, the maximum fluctuation range is 0.264. Fig. 2B shows the relationships among average fictional coefficient (fca), frictional coefficient range (Rf) and sliding velocity for the BMG specimens. The experiment results obtained under these conditions are summarized in Table 1. It can be found that, during the linear reciprocating sliding motion processes of GCr15 steel balls under a nominal load of 3 N, the maximum frictional coefficient (fcm) of the BMG fluctuates in the range of 0.302– 0.404 and the average frictional coefficient locates between 0.244 and 0.302. With the increase of sliding velocity, the average frictional coefficient increases gradually, while the frictional coefficient range presents an upward trend in a wave style on the whole.
Please cite this article as: Tao P, et al. Research on friction and wear behavior of a bulk metallic glass under different sliding velocity. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2015.03.075i
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132
P. Tao et al. / Materials Letters ∎ (∎∎∎∎) ∎∎∎–∎∎∎
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
Table 1 Characteristic parameters of frictional coefficient under P¼ 3 N with different Vss. Nrs
Vs (mm/min)
fcm
Rf
fca
50 50 50 50 50
50 100 150 200 250
0.349 0.302 0.350 0.319 0.444
0.189 0.175 0.215 0.209 0.264
0.244 0.257 0.272 0.276 0.302
3
These can be due to following reasons. At low and moderate sliding velocities, the friction is mainly caused by the local adhesion contact and shearing of contact areas. The frictional resistance produces surface heat, which always has been regarded as a temporary and local phenomenon, resulting in the fusion and aggregation of the broken surface layer alloys. [12]. The grinding trace width (GTW) locates between 36 μm and 227 μm and descends gradually with increasing sliding velocity, as shown in Fig. 3, indicating that the smaller the sliding velocity, the more serious the wear extent, and vice versa. At smaller sliding velocities, the numbers of alloy scrapes are relatively larger and the wear mechanism inclines to the combined effects of continuous wear, occlusion or bite welding, adhesive wear and abrasive wear. With the increase of sliding velocity, the numbers of the alloy scrapes reduce gradually and the wear mechanism changes gradually to a combined result of slight bite or bite welding and continuous wear.
4. Conclusions
Fig. 3. GTW as a function of Vs with P¼ 3 N and Nrs ¼ 50 for the alloys. (A and B) SEM images of middle and end grinding traces with Vs ¼150 mm/min; (C–F) SEM images of grinding traces with Vs ¼ 50, 100, 200 and 250 mm/min, respectively.
SEM morphological images of middle and end grinding traces tested at a sliding velocity of 150 mm/min are shown in insets A and B in Fig. 3. The grinding trace exhibits smooth linear furrows, on both sides of which some heaping alloy scraps can be observed, as seen in inset A, while at the ends of which these accumulation extent of surface alloy scraps becomes more serious and the accumulation surface alloy scraps present a preferred orientation, along the arrow direction shown in inset B. These friction and wear behaviors are in line with the welding, shearing and plowing theory proposed by Bowden [11]. The high pressure between the GCr15 steel ball and the surface of the BMG will bond the contact points. Then during the relative sliding process in the contact surface, partial bonded connection points will be sheared off and cut off. The asperities of the steel ball plowing the surface of the BMG will cause the formation of friction adhesion component, which will shear and plow the surface layer alloy of the BMG continuously. Then the broken surface layer alloy pieces formed will be pushed towards both sides and ends of the grinding trace, leading to the formation of typical surface material transfer phenomena in the process of metal’s friction and wear [12]. Insets C–F show the SEM morphological images of grinding traces tested at Vs ¼50, 100, 200 and 250 mm/min, respectively. Combined with inset B, it can be found that at smaller sliding velocities there are more alloy debrises torn from the contact areas of the bonded surface in the course of sliding processes. While at larger sliding velocities, relatively smaller alloy scrapses can be observed. On both sides of the grinding traces, a gradual increasing surface layer alloy debrises in concentration state to be transferred can be seen.
The sliding velocity significantly affects the friction and wear behaviors of the BMG. During the linear reciprocating sliding friction and wear tests, the average frictional coefficient locates between 0.244 and 0.302 and increases gradually with increasing sliding velocity. The grinding trace width locates between 36 μm and 227 μm and descends gradually with increasing sliding velocity. The grinding traces exhibit smooth linear furrows. The smaller the sliding velocity is, the more serious the wear and tear is. At smaller sliding velocities, the numbers of alloy scrapes in the grinding traces are relatively larger and the wear mechanism inclines to the combined effects of continuous wear, occlusion or bite welding, adhesive wear and abrasive wear. With the increase of sliding velocity, the numbers of the alloy scrapes reduce gradually and the wear mechanism changes gradually to a combined result of slight bite or bite welding and continuous wear.
Acknowledgements This work is supported by the National Natural Science Foundation of China (51201038), the Higher Specialized Research Foundation for Doctoral Program (20124420120009, 20124420110007), the National Natural Science Foundation of Guangdong (S2012040007575), and the CPGPME (2012B091100133, 2012B091100099, 2012B091100303). References [1] Kim J. Mater Lett 2014;130:160–3. [2] Kawashima A, Wada T, Ohmura K, Xie GQ, Inoue A. Mater Sci Eng, A 2012;542:140–6. [3] Wang L, Chao YS. Mater Lett 2012;69:76–8. [4] Zhang SG, Li JG. Mater Lett 2012;75:179–82. [5] Duan HT, Tu JS, Du SM, Kou HC, Li Y, Wang JP, Chen ZW, Li J. Mater Des 2011;32:4573–9. [6] Inoue A, Zhang T, Ishihara S, Saida J, Matsushita M. Scr Mater 2001;44:1615–9. [7] Hishiyama N, Amiya K, Inoue A. J Non-Cryst Solids 2007;353:3615–21. [8] Monnet G, Pouchon MA. Mater Lett 2013;98:128–30. [9] Geringer J, Macdonald DD. Mater Lett 2014;134:152–7. [10] Fleury E, Lee SM, Ahn HS, Kim WT, Kim DH. Mater Sci Eng, A 2007;375-377:276–9. [11] Dowson D, Higginson GR. Elastohydrodynamic lubrication. Oxford: Pergamon; 1966. [12] Moore DF. Principle and applications of tribology. London: Robert Maxwell, MC; 1975.
Please cite this article as: Tao P, et al. Research on friction and wear behavior of a bulk metallic glass under different sliding velocity. Mater Lett (2015), http://dx.doi.org/10.1016/j.matlet.2015.03.075i
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125