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Joining of high thermal-expansion mismatched C-SiC composite and stainless steel by an Ag + Ti + Mo mixed powder filler
Materials Letters 256 (2019) 126632
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Joining of high thermal-expansion mismatched C-SiC composite and stainless steel by an Ag + Ti + Mo mixed powder filler Wanli Wang, Yonglei Wang, Jihua Huang ⇑, Jian Yang, Shuhai Chen, Xingke Zhao School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, PR China
a r t i c l e
i n f o
Article history: Received 2 July 2019 Received in revised form 2 September 2019 Accepted 4 September 2019 Available online 5 September 2019 Keywords: Ceramic composites 304 stainless steel Residual thermal stress Interfaces
a b s t r a c t High thermal-expansion mismatched C-SiC composite and 304 stainless steel have been bonded by a 72Ag + 18Ti + 10Mo (at%) mixed powder filler. At the bonding temperature (1020 °C), the filler was in semi-solid state, i.e. solid-liquid mixed state of Mo particles, TiAg grains and Ag(Ti) liquid. Microstructural analysis indicated that the high activity and viscosity of the semi-solid filler help to obtain a large-thickness homogeneous joining layer (416 mm), in which Mo particles were clad by (Ti,Mo) solid solution and uniformly dispersed in Ag matrix together with the TiAg grains. The large thickness joining layer mainly composed of low coefficient of thermal expansion (CTE) Mo particles and ductile Ag matrix can effectively reduce the high residual stresses of the joint caused by the thermalexpansion mismatch between the dissimilar materials. Additionally, interfaces between the base materials and the joining layer were well bonded without continuous layered brittle compounds. The interfacial reaction products at C-SiC side were TiC, Ti5Si3 and Ti3SiC2 grains in Ag matrix. At 304 interface, Ti2Ni + Ti (Fe,Ni) compounds grew in columnar and gathered nearby. The characteristics of the joining layer and the bonding interfaces contribute to the high joint strength. The average shear strength of the joint at room temperature was 156 MPa. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction The joining of Carbon-carbon composites (C–C) and Carbonsilicon carbide composites (C-SiC) with metals has a strong application demand in the aerospace field [1]. Brazing is recognized as the most feasible and convenient method for joining the two dissimilar materials. However, large residual stresses caused by the high thermal-expansion mismatch between the composites and metals will seriously influence mechanical properties of the bonded joint, and even lead to catastrophic failure. To cope with this problem, ductile interlayers or low CTE particle reinforced filler materials have been applied in the joining of C–C or C-SiC composites with metals, such as using Ti-Cu bi-foil for joining C-SiC to Nb (aNb = 7.2 10 6 K 1) [2], Ni-based metallic glass interlayers were used for brazing C-SiC to Ti (aTi = 8.6 10 6 K 1) [3], using AgCuTi + SiC/TiC and TiZrCuNi + W composite filler for brazing CSiC to TC4 alloy (aTC4 = 8.7 10 6 K 1) [4–7], Cu/TiZrCuNi foils was designed for joining C–C to TC4 alloy [8], using TiH2-Ni-B filler for brazing C-SiC to TiAl alloy (aTiAl = 10 10 6 K 1) [9], composite filler of Cu foils, Ti foils and Mo particles were used for the join-
⇑ Corresponding author. E-mail address: [email protected] (J. Huang). https://doi.org/10.1016/j.matlet.2019.126632 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
ing of 2.5D C-SiC and GH783 alloy (aGH783 = 10.08 10 6 K 1) [10]. The filler materials in the previous researches had successfully realized the reliable joining between C–C or C-SiC composites and low CTE metals, but for the joining of composites and high CTE metals, cracks were usually formed in the joints [3,11]. The joining of C–C or C-SiC composites with high CTE metals, especially 304 stainless steel (a304 = 17.4 10 6 K 1), GH3044 superalloy (aGH3044 = 16.3 10 6 K 1), etc., which are wildly used in aerospace field, is still a challenge. In this paper, a mixed powder of 72Ag + 18Ti + 10Mo (at%) was used as filler material for bonding high thermal-expansion mismatched C-SiC composite and 304 stainless steel. At the bonding temperature (1020 °C), the filler material would be in semi-solid state of in-situ formed TiAg, Ag(Ti) liquid and Mo particles. The high viscosity of the semi-solid filler help to obtain a largethickness joining layer, in which the low CTE Mo particles (aMo = 5.1 10 6 K 1) serves to decrease the CTE of the joining layer. The large-thickness joining layer would be beneficial to reduce the shear strain of the joint and the ductile Ag matrix would contribute to accommodate the large strain mismatch by elastic deformation. Microstructure, mechanical properties and formation mechanism of the joint were investigated.
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W. Wang et al. / Materials Letters 256 (2019) 126632
Fig. 1. Backscattered electron images of the C-SiC/304 joint bonded at 1020 °C for 30 min using the 72Ag + 18Ti + 10Mo (at%) filler: (a) overall structure of the joint; (b) the joining layer under different magnification; (c) the C-SiC side interface, and (d) the 304 side interface.
Table 1 Chemical constituent of each phase in the joint (at%). Position
Ti
Si
Ag
C
Fe
Ni
Mo
Cr
Possible phase
P1 P2 P3 P4 P5 P6 P7 P8
— 56.11 0.57 17.95 41.41 92.50 57.09 3.73
— — — — 12.83 — 2.05 —
— 15.60 99.43 82.05 4.10 7.50 0.93 0.38
— — — — 41.66 — — —
— — — — — — 28.92 67.92
— — — — — — 11.01 1.27
100.0 28.29 — — — — — —
— — — —
Mo (Ti,Mo) Ag TiAg + Ag TiC + Ti5Si3 + Ti3SiC2 b-Ti Ti2Ni + Ti(Fe,Ni) Ti5Fe17Cr7 + Fe(Cr)
2. Experimental The C-SiC composite was fabricated by polymer infiltration pyrolysis coupled with chemical vapor infiltration. Its density is 1.8 g/cm3, porosity is 10–15 vol%, and CTE is 0.29 3.1 10 6 K 1. The C-SiC composite and 304 stainless steel were processed into 5 mm 5 mm 5 mm and 10 mm 10 mm 3 mm pieces. The surfaces to be bonded were polished by abrasive papers of 400 mesh. All the specimens were ultrasonically cleaned by alcohol and then dried below 50 °C. The filler material was the powdermixture of Ag (3 5 lm), Ti (20 30 lm), and Mo (3 5 lm)
— — 26.70
powders according to the composition of 72Ag + 18Ti + 10Mo (at %). It was kept in a vacuum drying oven before using. The filler material was transferred into a paste by a-Terpineol and placed between C-SiC composite and 304 stainless steel with a thickness of 0.6 0.7 mm. The bonding temperature was fixed at 1020 °C, bonding time was 30 min, heating rate was 15 °C/ min, and the vacuum was kept under 6.0 10 3 Pa. All the specimens were furnace-cooled to room temperature. Microstructures of the joints were investigated by the field emission scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer (EDS). Phase structure of the joints was examined by X-
W. Wang et al. / Materials Letters 256 (2019) 126632
3
Fig. 2. XRD patterns of the joint: (a) the joining layer and (b) C-SiC side interface.
Fig. 3. (a) Schematic diagram of the joining process and (b) Ag-Ti binary phase diagram.
ray diffraction (XRD). Testing method for shear strength of the bonded joints was referred to Ref. [7].
3. Results and discussion Fig. 1 presents the microstructures of the C-SiC/304 joint bonded by the Ag + Ti + Mo filler at 1020 °C for 30 min. As shown, a compact and homogeneous composite joining layer with large thickness (416 mm) was formed between the two base materials. From Fig. 1c and d, it is obvious that the interfaces between the joining layer and the base materials were bonded well without continuous layered brittle compounds which were harmful to the joint strength. According to the EDS (in Table 1) and XRD (in Fig. 2) results, it can be inferred that the joining layer was consisted of Mo particles, (Ti,Mo) solid solution, Ag matrix, TiAg grains and few residual Ti particles. The Mo particles which could reduce the CTE mismatch between the C-SiC and joining layer [12] were clad by (Ti,Mo) and uniformly dispersed in the ductile Ag matrix. The TiAg grains in-situ formed during bonding process existed around Mo parti-
cles. All of them contributed to the formation of the largethickness joining layer. According to Refs. [13,14], the calculated CTE and elastic modulus of the joining layer were 15 10 6 K 1 and 88 GPa, respectively. At C-SiC composite side, the interfacial reaction products were TiC, Ti5Si3 and Ti3SiC2 grains existing in Ag matrix. Ti2Ni + Ti(Fe,Ni) grew as columnar crystal with a narrow spacing at 304 side interface and gathered nearby. The average shear strength of the joint at room temperature was 156 MPa. The large-thickness homogeneous Mop/Ag composite joining layer and the moderate interfacial reaction contributed to the high joint strength. The bonding process of C-SiC composite and 304 stainless steel by Ag + Ti + Mo filler can be described using the conceptual model presented in Fig. 3(a). When the specimen was heated to the bonding temperature (1020 °C) (a-i), the Ag powders melted and Ti particles dissolved into the molten Ag (a-ii). Some fine TiAg grains insitu formed and the Mo particles were surrounded by the solidliquid mixture of TiAg grains and Ag(Ti) liquid (Fig. 3b). Due to the existence of Ti, the semi-solid filler had good wettability to both the base materials and the Mo particles. Interfacial reaction occurred between the filler and the base materials. Simultaneously,
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W. Wang et al. / Materials Letters 256 (2019) 126632
Mo particles reacted with Ti and were dispersed into single particle (a-iii). As the reaction proceed, Mo particles were uniformly distributed in the brazing seam. High viscosity of the semi-solid filler not only helped to prevent Mo particles from macro segregation but also contributed to obtain a large-thickness joining layer. Finally, the joint were obtained by the appropriate interfacial reaction and the formation of the efficient stress-relaxing joining layer (a-iv). 4. Conclusion C-SiC composite and 304 stainless steel were successfully bonded by the 72Ag + 18Ti + 10Mo (at%) mixed powder filler at 1020 °C for 30 min. A large-thickness homogeneous joining layer (416 mm) was formed after bonding, in which Mo particles were clad by (Ti,Mo) solid solution and uniformly dispersed in Ag matrix together with TiAg grains. The large-thickness joining layer can effectively reduce the high residual stresses in the joint. Interfaces between the base materials and the joining layer were well bonded without continuous layered brittle compounds. The characteristics of the joining layer and the bonding interfaces contribute to the high joint strength, which was 156 MPa at room temperature. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments This research was supported by National Natural Science Foundation of China (No. 51875038) and National Defense Pre-Research Foundation of China (No. 61409230507 and No. 61409230505).
References [1] S. Schmidt, S. Beyer, H. Knabe, H. Immich, R. Meistring, A. Gessler, Advanced ceramic matrix composite materials for current and future propulsion technology applications, Acta Astronaut. 55 (2004) 409–420. [2] J.T. Xiong, J.L. Li, F.S. Zhang, W.D. Huang, Joining of 3D C/SiC composites to niobium alloy, Scripta Mater. 55 (2006) 151–154. [3] M. Singh, R. Asthana, T.P. Shpargel, Brazing of ceramic-matrix composites to Ti and Haste alloy using Ni-base metallic glass interlayers, Mater. Sci. Eng. AStruct. 498 (2008) 19–30. [4] J.H. Xiong, J.H. Huang, G.B. Lin, H. Zhang, X.K. Zhao, Joining of Cf/SiC composite to TC4 using Ag-Cu-Ti-SiC composite filler material, Powder Metall. 54 (2011) 269–272. [5] G.W. Liu, X.Z. Zhang, J. Yang, G.J. Qiao, Recent advances in joining of SiC-based materials (monolithic SiC and SiCf/SiC composites): joining processes, joint strength, and interfacial behavior, J. Adv. Ceram. 8 (2019) 19–38. [6] B. Cui, J.H. Huang, J.H. Xiong, H. Zhang, Reaction-composite brazing of carbon fiber reinforced SiC composite and TC4 alloy using Ag-Cu-Ti-(Ti+C) mixed powder, Mater. Sci. Eng. A-Struct. 562 (2013) 203–210. [7] B. Cui, J.H. Huang, C. Cai, S.H. Chen, X.K. Zhao, Microstructures and mechanical properties of Cf/SiC composite and TC4 alloy joints brazed with (Ti-Zr-Cu-Ni) +W composite filler materials, Compos. Sci. Technol. 97 (2014) 19–26. [8] X.R. Song, H.J. Li, V. Casalegno, M. Salvo, M. Ferraris, X.R. Zeng, Microstructure and mechanical properties of C/C composite/Ti6Al4V joints with a Cu/TiCuZrNi composite brazing alloy, Ceram. Int. 42 (2016) 6347–6354. [9] Z.W. Yang, L.X. Zhang, X.Y. Tian, Y.Z. Liu, P. He, J.C. Feng, Interfacial microstructure and mechanical properties of TiAl and C/SiC joint brazed with TiH2-Ni-B brazing powder, Mater. Charact. 79 (2013) 52–59. [10] X. Wang, L.F. Cheng, S.W. Fan, L.T. Zhang, Microstructure and mechanical properties of the GH783/2.5D C/SiC joints brazed with Cu-Ti+Mo composite filler, Mater. Des. 36 (2012) 499–504. [11] D.Y. Fan, J.H. Huang, Y.H. Wang, S.H. Chen, X.K. Zhao, Active brazing of carbon fiber reinforced SiC composite and 304 stainless steel with Ti–Zr–Be, Mater. Sci. Eng. A-Struct. 617 (2014) 66–72. [12] J.Y. Liu, J. Zhang, C.F. Liu, T.P. Wang, Microstructure and mechanical properties of porous Si3N4/Invar joints brazed with Ag-Cu-Ti+Mo/Cu/Ag-Cu multilayered composite filler, Ceram. Int. 43 (2017) 11668–11675. [13] J. Ba, H. Li, B. Ren, B.X. Qi, X.H. Zheng, R. Ning, Q.J. Lei, J. Cao, W. Cai, J.C. Feng, In situ formation of TiB whiskers to reinforce SiO2-BN/Ti6Al4V brazed joints, Ceram. Int. 45 (2019) 8054–8057. [14] J. Ba, X.H. Zheng, R. Ning, J.H. Lin, J.L. Qi, J. Cao, W. Cai, J.C. Feng, C/SiC composite-Ti6Al4V joints brazed with negative thermal expansion ZrP2WO12 nanoparticle reinforced AgCu alloy, J. Eur. Ceram. Soc. 39 (2019) 755–761.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Joining of high thermal-expansion mismatched C-SiC composite and stainless steel by an Ag + Ti + Mo mixed powder filler Wanli Wang, Yonglei Wang, Jihua Huang ⇑, Jian Yang, Shuhai Chen, Xingke Zhao School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, PR China
a r t i c l e
i n f o
Article history: Received 2 July 2019 Received in revised form 2 September 2019 Accepted 4 September 2019 Available online 5 September 2019 Keywords: Ceramic composites 304 stainless steel Residual thermal stress Interfaces
a b s t r a c t High thermal-expansion mismatched C-SiC composite and 304 stainless steel have been bonded by a 72Ag + 18Ti + 10Mo (at%) mixed powder filler. At the bonding temperature (1020 °C), the filler was in semi-solid state, i.e. solid-liquid mixed state of Mo particles, TiAg grains and Ag(Ti) liquid. Microstructural analysis indicated that the high activity and viscosity of the semi-solid filler help to obtain a large-thickness homogeneous joining layer (416 mm), in which Mo particles were clad by (Ti,Mo) solid solution and uniformly dispersed in Ag matrix together with the TiAg grains. The large thickness joining layer mainly composed of low coefficient of thermal expansion (CTE) Mo particles and ductile Ag matrix can effectively reduce the high residual stresses of the joint caused by the thermalexpansion mismatch between the dissimilar materials. Additionally, interfaces between the base materials and the joining layer were well bonded without continuous layered brittle compounds. The interfacial reaction products at C-SiC side were TiC, Ti5Si3 and Ti3SiC2 grains in Ag matrix. At 304 interface, Ti2Ni + Ti (Fe,Ni) compounds grew in columnar and gathered nearby. The characteristics of the joining layer and the bonding interfaces contribute to the high joint strength. The average shear strength of the joint at room temperature was 156 MPa. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction The joining of Carbon-carbon composites (C–C) and Carbonsilicon carbide composites (C-SiC) with metals has a strong application demand in the aerospace field [1]. Brazing is recognized as the most feasible and convenient method for joining the two dissimilar materials. However, large residual stresses caused by the high thermal-expansion mismatch between the composites and metals will seriously influence mechanical properties of the bonded joint, and even lead to catastrophic failure. To cope with this problem, ductile interlayers or low CTE particle reinforced filler materials have been applied in the joining of C–C or C-SiC composites with metals, such as using Ti-Cu bi-foil for joining C-SiC to Nb (aNb = 7.2 10 6 K 1) [2], Ni-based metallic glass interlayers were used for brazing C-SiC to Ti (aTi = 8.6 10 6 K 1) [3], using AgCuTi + SiC/TiC and TiZrCuNi + W composite filler for brazing CSiC to TC4 alloy (aTC4 = 8.7 10 6 K 1) [4–7], Cu/TiZrCuNi foils was designed for joining C–C to TC4 alloy [8], using TiH2-Ni-B filler for brazing C-SiC to TiAl alloy (aTiAl = 10 10 6 K 1) [9], composite filler of Cu foils, Ti foils and Mo particles were used for the join-
⇑ Corresponding author. E-mail address: [email protected] (J. Huang). https://doi.org/10.1016/j.matlet.2019.126632 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
ing of 2.5D C-SiC and GH783 alloy (aGH783 = 10.08 10 6 K 1) [10]. The filler materials in the previous researches had successfully realized the reliable joining between C–C or C-SiC composites and low CTE metals, but for the joining of composites and high CTE metals, cracks were usually formed in the joints [3,11]. The joining of C–C or C-SiC composites with high CTE metals, especially 304 stainless steel (a304 = 17.4 10 6 K 1), GH3044 superalloy (aGH3044 = 16.3 10 6 K 1), etc., which are wildly used in aerospace field, is still a challenge. In this paper, a mixed powder of 72Ag + 18Ti + 10Mo (at%) was used as filler material for bonding high thermal-expansion mismatched C-SiC composite and 304 stainless steel. At the bonding temperature (1020 °C), the filler material would be in semi-solid state of in-situ formed TiAg, Ag(Ti) liquid and Mo particles. The high viscosity of the semi-solid filler help to obtain a largethickness joining layer, in which the low CTE Mo particles (aMo = 5.1 10 6 K 1) serves to decrease the CTE of the joining layer. The large-thickness joining layer would be beneficial to reduce the shear strain of the joint and the ductile Ag matrix would contribute to accommodate the large strain mismatch by elastic deformation. Microstructure, mechanical properties and formation mechanism of the joint were investigated.
2
W. Wang et al. / Materials Letters 256 (2019) 126632
Fig. 1. Backscattered electron images of the C-SiC/304 joint bonded at 1020 °C for 30 min using the 72Ag + 18Ti + 10Mo (at%) filler: (a) overall structure of the joint; (b) the joining layer under different magnification; (c) the C-SiC side interface, and (d) the 304 side interface.
Table 1 Chemical constituent of each phase in the joint (at%). Position
Ti
Si
Ag
C
Fe
Ni
Mo
Cr
Possible phase
P1 P2 P3 P4 P5 P6 P7 P8
— 56.11 0.57 17.95 41.41 92.50 57.09 3.73
— — — — 12.83 — 2.05 —
— 15.60 99.43 82.05 4.10 7.50 0.93 0.38
— — — — 41.66 — — —
— — — — — — 28.92 67.92
— — — — — — 11.01 1.27
100.0 28.29 — — — — — —
— — — —
Mo (Ti,Mo) Ag TiAg + Ag TiC + Ti5Si3 + Ti3SiC2 b-Ti Ti2Ni + Ti(Fe,Ni) Ti5Fe17Cr7 + Fe(Cr)
2. Experimental The C-SiC composite was fabricated by polymer infiltration pyrolysis coupled with chemical vapor infiltration. Its density is 1.8 g/cm3, porosity is 10–15 vol%, and CTE is 0.29 3.1 10 6 K 1. The C-SiC composite and 304 stainless steel were processed into 5 mm 5 mm 5 mm and 10 mm 10 mm 3 mm pieces. The surfaces to be bonded were polished by abrasive papers of 400 mesh. All the specimens were ultrasonically cleaned by alcohol and then dried below 50 °C. The filler material was the powdermixture of Ag (3 5 lm), Ti (20 30 lm), and Mo (3 5 lm)
— — 26.70
powders according to the composition of 72Ag + 18Ti + 10Mo (at %). It was kept in a vacuum drying oven before using. The filler material was transferred into a paste by a-Terpineol and placed between C-SiC composite and 304 stainless steel with a thickness of 0.6 0.7 mm. The bonding temperature was fixed at 1020 °C, bonding time was 30 min, heating rate was 15 °C/ min, and the vacuum was kept under 6.0 10 3 Pa. All the specimens were furnace-cooled to room temperature. Microstructures of the joints were investigated by the field emission scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer (EDS). Phase structure of the joints was examined by X-
W. Wang et al. / Materials Letters 256 (2019) 126632
3
Fig. 2. XRD patterns of the joint: (a) the joining layer and (b) C-SiC side interface.
Fig. 3. (a) Schematic diagram of the joining process and (b) Ag-Ti binary phase diagram.
ray diffraction (XRD). Testing method for shear strength of the bonded joints was referred to Ref. [7].
3. Results and discussion Fig. 1 presents the microstructures of the C-SiC/304 joint bonded by the Ag + Ti + Mo filler at 1020 °C for 30 min. As shown, a compact and homogeneous composite joining layer with large thickness (416 mm) was formed between the two base materials. From Fig. 1c and d, it is obvious that the interfaces between the joining layer and the base materials were bonded well without continuous layered brittle compounds which were harmful to the joint strength. According to the EDS (in Table 1) and XRD (in Fig. 2) results, it can be inferred that the joining layer was consisted of Mo particles, (Ti,Mo) solid solution, Ag matrix, TiAg grains and few residual Ti particles. The Mo particles which could reduce the CTE mismatch between the C-SiC and joining layer [12] were clad by (Ti,Mo) and uniformly dispersed in the ductile Ag matrix. The TiAg grains in-situ formed during bonding process existed around Mo parti-
cles. All of them contributed to the formation of the largethickness joining layer. According to Refs. [13,14], the calculated CTE and elastic modulus of the joining layer were 15 10 6 K 1 and 88 GPa, respectively. At C-SiC composite side, the interfacial reaction products were TiC, Ti5Si3 and Ti3SiC2 grains existing in Ag matrix. Ti2Ni + Ti(Fe,Ni) grew as columnar crystal with a narrow spacing at 304 side interface and gathered nearby. The average shear strength of the joint at room temperature was 156 MPa. The large-thickness homogeneous Mop/Ag composite joining layer and the moderate interfacial reaction contributed to the high joint strength. The bonding process of C-SiC composite and 304 stainless steel by Ag + Ti + Mo filler can be described using the conceptual model presented in Fig. 3(a). When the specimen was heated to the bonding temperature (1020 °C) (a-i), the Ag powders melted and Ti particles dissolved into the molten Ag (a-ii). Some fine TiAg grains insitu formed and the Mo particles were surrounded by the solidliquid mixture of TiAg grains and Ag(Ti) liquid (Fig. 3b). Due to the existence of Ti, the semi-solid filler had good wettability to both the base materials and the Mo particles. Interfacial reaction occurred between the filler and the base materials. Simultaneously,
4
W. Wang et al. / Materials Letters 256 (2019) 126632
Mo particles reacted with Ti and were dispersed into single particle (a-iii). As the reaction proceed, Mo particles were uniformly distributed in the brazing seam. High viscosity of the semi-solid filler not only helped to prevent Mo particles from macro segregation but also contributed to obtain a large-thickness joining layer. Finally, the joint were obtained by the appropriate interfacial reaction and the formation of the efficient stress-relaxing joining layer (a-iv). 4. Conclusion C-SiC composite and 304 stainless steel were successfully bonded by the 72Ag + 18Ti + 10Mo (at%) mixed powder filler at 1020 °C for 30 min. A large-thickness homogeneous joining layer (416 mm) was formed after bonding, in which Mo particles were clad by (Ti,Mo) solid solution and uniformly dispersed in Ag matrix together with TiAg grains. The large-thickness joining layer can effectively reduce the high residual stresses in the joint. Interfaces between the base materials and the joining layer were well bonded without continuous layered brittle compounds. The characteristics of the joining layer and the bonding interfaces contribute to the high joint strength, which was 156 MPa at room temperature. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments This research was supported by National Natural Science Foundation of China (No. 51875038) and National Defense Pre-Research Foundation of China (No. 61409230507 and No. 61409230505).
References [1] S. Schmidt, S. Beyer, H. Knabe, H. Immich, R. Meistring, A. Gessler, Advanced ceramic matrix composite materials for current and future propulsion technology applications, Acta Astronaut. 55 (2004) 409–420. [2] J.T. Xiong, J.L. Li, F.S. Zhang, W.D. Huang, Joining of 3D C/SiC composites to niobium alloy, Scripta Mater. 55 (2006) 151–154. [3] M. Singh, R. Asthana, T.P. Shpargel, Brazing of ceramic-matrix composites to Ti and Haste alloy using Ni-base metallic glass interlayers, Mater. Sci. Eng. AStruct. 498 (2008) 19–30. [4] J.H. Xiong, J.H. Huang, G.B. Lin, H. Zhang, X.K. Zhao, Joining of Cf/SiC composite to TC4 using Ag-Cu-Ti-SiC composite filler material, Powder Metall. 54 (2011) 269–272. [5] G.W. Liu, X.Z. Zhang, J. Yang, G.J. Qiao, Recent advances in joining of SiC-based materials (monolithic SiC and SiCf/SiC composites): joining processes, joint strength, and interfacial behavior, J. Adv. Ceram. 8 (2019) 19–38. [6] B. Cui, J.H. Huang, J.H. Xiong, H. Zhang, Reaction-composite brazing of carbon fiber reinforced SiC composite and TC4 alloy using Ag-Cu-Ti-(Ti+C) mixed powder, Mater. Sci. Eng. A-Struct. 562 (2013) 203–210. [7] B. Cui, J.H. Huang, C. Cai, S.H. Chen, X.K. Zhao, Microstructures and mechanical properties of Cf/SiC composite and TC4 alloy joints brazed with (Ti-Zr-Cu-Ni) +W composite filler materials, Compos. Sci. Technol. 97 (2014) 19–26. [8] X.R. Song, H.J. Li, V. Casalegno, M. Salvo, M. Ferraris, X.R. Zeng, Microstructure and mechanical properties of C/C composite/Ti6Al4V joints with a Cu/TiCuZrNi composite brazing alloy, Ceram. Int. 42 (2016) 6347–6354. [9] Z.W. Yang, L.X. Zhang, X.Y. Tian, Y.Z. Liu, P. He, J.C. Feng, Interfacial microstructure and mechanical properties of TiAl and C/SiC joint brazed with TiH2-Ni-B brazing powder, Mater. Charact. 79 (2013) 52–59. [10] X. Wang, L.F. Cheng, S.W. Fan, L.T. Zhang, Microstructure and mechanical properties of the GH783/2.5D C/SiC joints brazed with Cu-Ti+Mo composite filler, Mater. Des. 36 (2012) 499–504. [11] D.Y. Fan, J.H. Huang, Y.H. Wang, S.H. Chen, X.K. Zhao, Active brazing of carbon fiber reinforced SiC composite and 304 stainless steel with Ti–Zr–Be, Mater. Sci. Eng. A-Struct. 617 (2014) 66–72. [12] J.Y. Liu, J. Zhang, C.F. Liu, T.P. Wang, Microstructure and mechanical properties of porous Si3N4/Invar joints brazed with Ag-Cu-Ti+Mo/Cu/Ag-Cu multilayered composite filler, Ceram. Int. 43 (2017) 11668–11675. [13] J. Ba, H. Li, B. Ren, B.X. Qi, X.H. Zheng, R. Ning, Q.J. Lei, J. Cao, W. Cai, J.C. Feng, In situ formation of TiB whiskers to reinforce SiO2-BN/Ti6Al4V brazed joints, Ceram. Int. 45 (2019) 8054–8057. [14] J. Ba, X.H. Zheng, R. Ning, J.H. Lin, J.L. Qi, J. Cao, W. Cai, J.C. Feng, C/SiC composite-Ti6Al4V joints brazed with negative thermal expansion ZrP2WO12 nanoparticle reinforced AgCu alloy, J. Eur. Ceram. Soc. 39 (2019) 755–761.