J. Cent. South Univ. (2018) 25: 1025−1032 DOI: https://doi.org/10.1007/s11771-018-3802-z

Partial transient-liquid-phase bonding of TiC cermet to using impulse pressuring with Ti/Cu/Nb interlayer

HUANG Li(黄利)1, SHENG Guang-min(盛光敏)1, LI Jia(李佳)2, HUANG Guang-jie(黄光杰)1, YUAN Xin-jian(袁新建)1

1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China; 2. Changan Commercial Vehicle Business Department, China Changan Automobile Group, Chongqing 400023, China

© Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Abstract: Partial transient liquid phase (PTLP) bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885 °C under a pulsed pressure of 2–10 MPa within durations in the range of 2–8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the σ phase with a limit solubility of Nb, a sequence of Ti–Cu intermetallic phases and solid solutions of Ni and Cu in α+β Ti in the reaction zone. The maximum strength of 106.7 MPa was obtained when the joint was bonded for 5 min, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti–Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner.

Key words: TiC cermet; transient liquid phase; impulse pressuring; mechanical property; fracture

Cite this article as: HUANG Li, SHENG Guang-min, LI Jia, HUANG Guang-jie, YUAN Xin-jian. Partial transient-liquid-phase bonding of TiC cermet to stainless steel using impulse pressuring with Ti/Cu/Nb interlayer [J]. Journal of Central South University, 2018, 25(5): 1025–1032. DOI: https://doi.org/10.1007/s11771-018-3802-z.

physical incompatibility, such as covalent nature of 1 Introduction cermets and coefficient of thermal expansion (CTE) mismatch between these materials [3–5]. TiC cermet was a promising material due to its Conventional fusion was infeasible in the excellent combination of desirable properties at case of dissimilar materials joining of refractory elevated temperature [1, 2]. However, the intensive TiC cermet (–3067 °C [6]) to steel owing to their application of TiC cermet is restricted for the poor different melting points, and would result in workability originated from its inherent brittleness. concentration of residual stress at the interface of A promising option to take advantage of the good the joints [7]. Partial transient liquid phase (PTLP) characteristics of cermets was to combine it with bonding, by contrast, has been demonstrated to be other metals, such as steel. one of the most practicable methods to effectively Selecting appropriate filler metal is critical for bond ceramics to steels. of TiC cermet to steel. The filler is required In PTLP bonding process, a eutectic liquid to be capable of accommodating their chemical and formed at the bonding interface allows the TiC

Foundation item: Project(51421001) supported by the National Natural Science Foundation of China; Projects(106112015CDJXZ138803, 106112015CDJXY130003) supported by the Fundamental Research Funds for the Central Universities, China Received date: 2016−10−13; Accepted date: 2017−02−23 Corresponding author: SHENG Guang-min, PhD, Professor; Tel: +86–23–65120787; E-mail: [email protected] 1026 J. Cent. South Univ. (2018) 25: 1025–1032 cermet/steel joint formation at much lower bonding all of these factors were in good shape to shorten temperature than conventional connection methods, the bonding time, and then accelerated the bonding which was improved by TLP. [8, 9]. In terms of process. cermet/steel brazing, a series of Ti-, Cu-, Nb- and In the present study, a modified diffusion Ni-based interlayers have been well documented. bonding technology, PTLP bonding using impulse Recently, the Ti/Cu/Ti [10], Ti/Ni/Ti [11] and pressuring with Ti/Cu/Nb interlayer was applied to Ti/Cu/Ni [12] interlayers used for PTLP bonding of realize robust bonding of TiC cermet to steel within ceramics to metal have been reported. Ti was the a significantly reduced duration. most attractive active element for almost all the structure ceramics [13]. A thin Cu and Ni interlayer 2 Experimental as melting point depressant was popularly used involving Ti because a low eutectic melting The base materials, hot pressure sintering liquid-phase can be formed above 875 °C and (HPS) TiC cermet and commercially stainless steel 942 °C, respectively [14]. It was also reported by (SS, 06Cr19Ni10), were processed into 3 mm× YANG et al [15] and MARKS et al [16] that the 4 mm×8 mm and 3 mm×8 mm×30 mm, respectively.

Si3N4/Inconel600 joint and Al2O3/Al2O3 joint can be As the multilayer metals, pure Ti, Cu, and Nb, with achieved respectively, and the average shear a thickness of 30 μm, 20 μm and 30 μm, were used. strength can reach to 90–142 MPa. Soft Nb was a The chemical compositions and room temperature suitable candidate to buffer the residual stress in the thermophysical properties of substrates and ceramic/metal joints attributed to its lower CTE interlayer are given in Tables 1 and 2. The mating value (7.2×10–6 K–1) compared to ceramics (TiC surfaces of the specimen were prepared by cermet: 7.4×10–6 K–1) and steel ((12–13)×10–6 K–1) conventional grinding and polishing techniques, [6, 17]. Therefore, an interlayer Ti/Cu/Nb was and subsequently cleaned in acetone to eradicate required to be capable of accommodating the any residual contamination. The assembly sequence incompatible chemical and physical properties of samples was TiC–Ti–Cu–Nb-SS, as displayed in between TiC cermet and steel in the present study. Figure 1(a). Bonding trials were performed in a In spite of successful Gleeble-1500D tester and the parameters were: achieved in above cases, it was noted that the temperature T=885 °C, pulsed compressive load diffusion bonding was time-consuming as 30– pmin=2 MPa and pmax=10 MPa, impulse frequency 120 min was generally required to complete the f=0.5 Hz, bonding time t=2–8 min under a pulsed bonding process [10–16]. A reduction in bonding compressive load, in vacuum maintained at 1× time, which can retard the excessive growth of 10–3 Pa. interfacial intermetallic compound (IMC), would be Subsequent to bonding, selected specimens in turn potentially contributed to the bonding were sectioned and microstructural observations strength. In this regards, it was of great interest to were conducted in field emission scanning electron shorten the bonding time by further optimizing the microscope (FEI-SEM, FEI Nova400) using back bonding circle, for the purpose of both productive scattered mode (BSE) to reveal the interfacial efficiency and cost saving. Auxiliary impulse reaction layers. Chemical concentration profile pressure can offer an advantage in the process of across the joints was determined using energy PTLP bonding because the pressure can enhance the dispersive spectroscope (EDS). Room temperature speed of the atomic diffusion [18]. The compressive shear tests were performed in a testing machine deformation generated by impulse pressure can fill (Instron 1342) at a crosshead speed of voids and lead to titanium grain refining [19], 0.025 mm/min to examine the mechanical which produced more grain boundaries to generate properties, as displayed in Figure 1. Fracture additional diffusion paths. Thus thermodynamically, morphologies were observed by SEM, and X-ray

Table 1 Chemical composition of substrates (wt %) Material Cr C Ti Ni W Mo Mn S P Fe TiC — 19.6 Balance 9.54 2.94 1.40 — — — — 06Cr19Ni10 18.67 0.12 — 8.43 — — 1.35 0.03 0.035 Balance

J. Cent. South Univ. (2018) 25: 1025–1032 1027 Table 2 Room temperature thermo-physical properties of Ti, Cu, Nb and substrates [6, 17] Material Melting point/K Coefficient of thermal expansion/(10–6 K–1) Modulus of elasticity/GPa Ti 1913–1943 9.4 115 Cu 1338–1355 16.92 125 Nb 2468 7.2 105 TiC 3067 7.4 410–510 06Cr19Ni10 1399–1455 12–13 193

load–displacement curve are given in Figure 2. The shear strength was determined by the formula σ=F/S (σ was the strength, MPa; F was the loading, kN; and S was the bonded acreage of the sample, 3 mm×8 mm). The TiC cermet/SS joint was destroyed at the maximum load and then the load decreased suddenly, shown in Figure 2(b). This meant that fracture of the TiC cermet/SS joint was a brittle manner. It was well known that the most important parameters for PTLP bonding, bonding temperature, pressure and bonding time, were not independent with each other. At a given temperature, the bonding time required to complete the bonding was

Figure 1 Schematic diagram: (a) Assembly of samples; (b) Shear test for bonded joints; (c) Technological curve of impulse pressuring diffusion bonding diffraction (XRD) was used to identify phase at the fracture.

3 Results and discussion

3.1 Mechanical properties Figure 2 Shear strength measurement: (a) Joints bonded Shear strength of the PTLP joints with the at different time; (b) Relationship between load and change of bonding time and the axial shear displacement

1028 J. Cent. South Univ. (2018) 25: 1025–1032 a function of the applied pressure. A higher pressure strength joint bonded for 5 min studied by SEM is would preferentially result in a reduced time shown in Figure 3(a). The micrograph exhibited an required. At the short time range of 2–3.5 min, the excellent bonding along the interface of the bonded joints exhibited a rather low strength of couples. A reaction and interdiffusion area was approximately 21–58.5 MPa. As the bonding time found at the TiC cermet/SS interface, and several increased, so does the number of impulses (f= distinct regions were observed on the micrograph. 0.5 Hz). When t<5 min, elemental diffusion Corresponding elemental concentration profile of gradually increased as the number of impulses this joint was conducted to identify the phase multiplies. The limited macroscopic deformation of constituent of the interfacial reaction layers, as the joint can be attributed to the increasing loading shown in Figure 3(b). cycle the substrate experienced, which further The SS/Nb interface was planar in character. It promoted the atomic diffusivity [19]. It was thus can be seen that there was a thin diffusion zone “1” deduced that the poor bonding quality of the joints rich in Fe and Cr, which could be the formation of σ was precisely because of the insufficient mass phase [14]. The average composition of this σ phase transfer of the reaction interface in such short was Fe 65.5at %, Cr 24.8at %, Ni 3.5at % and Nb bonding time. The joint strength was notably 6.2at %, as listed in Table 3. Owing to the reactive improved to 106.7 MPa when the bonding time nature of Nb, metallurgical bonding can be readily increased to 5 min. The improvement can be formed at the SS/Nb interface via σ phase attributed to the enhanced interdiffusion at the with a low solubility of Nb, as shown in Figure 3. bonding interface. Obviously, atomic diffusivity However, since the mutual solubility of the Nb–σ was dominant in leading to the observed change phase system was limited, relatively prolonged since atomic diffusion has a decisive influence on duration was required to achieve adequate forming the bonded joint, thereby affecting the interdiffusion, which was a time-dependent process. strength of the joint significantly. However, when Adjacent to the SS/Nb interface, no element t>5 min, the joint shear strength decreased steadily, other than Nb can be detected from the elemental which can be ascribed to the ease of the concentration profile. Therefore, this was the deformation and thickening of brittle phases with a remnant Nb layer. The remnant Nb layer with low further increase in bonding time [20]. In all cases, CTE value (7.2×10–6 K–1) between TiC cermet and the excellent mechanical property of joints SS can be a significant player to relieve the residual indicated that good metallurgical bonding was stress. Close to the remnant Nb interlayer, three achieved at the appropriate bonding parameters. distinct eutectic Cu–Ti layers, marked “2”, “3” and “4”, were also detected, and there was a plateau in 3.2 Microstructure characterization the corresponding concentration profile of these Detailed microstructure of the maximum layers. The average compositions of these layers

Figure 3 SEM micrograph of joint interface at bonding time of 5 min (a) and corresponding elemental concentration profile (b)

J. Cent. South Univ. (2018) 25: 1025–1032 1029 Table 3 Chemical composition of marked regions in Figure 3(a) Region x(Fe)/% x(Cr)/% x(Nb)/% x(Cu)/% x(Ti)/% x(Ni)/% Possible phase 1 65.5 24.8 6.2 — — 3.5 σ

2 — — 1.5 71.8 26.7 — TiCu4

3 — — 4.3 60.5 35.2 — Ti2Cu3

4 — — 3.4 31.9 64.7 — Ti2Cu 5 — — — 2.3 92.6 5.1 α+β Ti respectively were: Ti 26.7 at %, Cu 71.8 at %, and continuous transition layers were approached across Nb 1.5 at % in layer “2”; Ti 35.2 at %, Cu 60.5 at %, the bonding interface. and Nb 4.3 at % in layer “3”; and Ti 64.7 at %, Cu 31.9 at %, and Nb 3.4 at % in layer “4”. XU 3.3 Fracture analysis et al [21] investigated the phase equilibria of the The fracture morphologies for all the TiC Cu–Nb–Ti system, which suggested that the cermet/SS joints under the SEM micrograph, solubility of Nb in Ti2Cu was determined to be irrespective of the bonding parameters, appeared 3.5 at %, whereas the solubility of Nb in TiCu4 was alike. A typical example of the maximum strength rather low, and the invariant reaction TiCu2↔ sample bonded under conditions of T=885 °C, p= TiCu4+Ti2Cu3 should occur at 850 °C. In 2–10 MPa, t=5 min, f=0.5 Hz is shown in Figure 4. combination with the EDS results and the The fracture surfaces as seen in Figure 4 consisted Cu–Nb–Ti ternary phase diagram, continuous IMC of gray matrix, white lumpy region and relatively layers, including TiCu4, Ti2Cu3 and Ti2Cu, were few dark blocks of different sizes and distribution. generated from layer “2” to “4” attributed to the The grains in the gray matrix magnified in interdiffusion of Ti and Cu. The final thickness of Figure 4(b) showed isometric and coarse the IMC layers was only about 22 μm after the morphology, but not metallic shine, which can be isothermal solidification and solid phase deduced to be TiC cermet. By contrast, extensive homogenization, compared to the original Cu and cleavage patterns were observed in the lumpy Ti in the thickness of 50 μm. It was attributed to the region and dark blocks, magnified in Figures 4(c) impulse pressure, which crowded out partial liquid and (d), respectively, from which it can be to reduce the thickness of IMC layers. Moreover, reasonably inferred that these regions were where Nb and Cu played a role as diffusion barrier the shear forces were concentrated, and the joints between Ti and SS, and Ti–Fe IMCs which have fail in a brittle manner. been recognized to be the most detrimental to the To further investigate this characterization, the joint strength successfully inhibited. EDS technique was used to identify the elemental Between the eutectic Cu–Ti layers and TiC composition of the lumpy region and dark blocks substrate, a thin hybrid layer “5” was observed, on the fracture surfaces, given in Table 4. The with the average composition Ti (92.6 at %), Ni average percentage of Cu and Ti in lumpy region (5.1 at %) and Cu (2.3 at %). The diffusion distance was 58.44 at% and 41.56 at% respectively. of Ti and Ni from cermet to interface was about 5 According to the Cu–Ti phase diagram [14], the μm. And the concentration profiles of both Ti and lumpy region was occupied mainly by Cu–Ti Ni in this layer exhibited smooth and continuous intermetallic phases. On the other hand, the average variations. Due to the diffusion of Ni, a β stabilizing percentage of Cu and Ni in the dark blocks was element, towards the Ti substrate, led to the only 2.1 at% and 4.9 at%, which was within the Cu formation of β Ti phase at bonding temperature. and Ni solubility limit in α+β Ti. Therefore, during the cooling stage, the hybrid α+β To further verify the fracture location, the Ti was formed in this layer because the β Ti existence of the phases on the fracture surfaces has transformed to α+β Ti aggregate under the phase also been identified by XRD of a fractured transformation point (882 °C) [22]. As the bonding specimen, displayed in Figure 5. The XRD patterns proceeded, due to the solid state interdiffusion of indicated that the Ti–Cu IMCs, (Ti, Ni) and TiC are elements, considerable mass transfer occurred and detected on both sides of the fracture, while the Nb

1030 J. Cent. South Univ. (2018) 25: 1025–1032

Figure 4 Fracture surface of sample: (a) TiC cermet side; (b) Enlarged micrograph of gray matrix; (c) Enlarged micrograph of white lumpy region; (d) Enlarged micrograph of dark blocks

Table 4 EDS analysis of fracture surface in Figures 4(c) maximum within the ceramics closed to reaction and (d) interface, which explains the fracture extension to Possible Zone x(Ti)/% x(Cu)/% x(Ni)/% TiC cermet. The stresses resulted in crack formation phase at the gaps either due to the thermal expansion Lumpy 41.56 58.44 — Ti–Cu IMCs region mismatch and subsequent differences in thermal Dark block 93.0 2.1 4.9 α+β Ti contraction in cooling or by the applied loads during indentation. Because the CTE of SS was and γ Fe phase were only detected on SS side. The higher than that of TiC ceramic, the tensile residual composition of (Ti, Ni) matched that of α+β Ti layer, stress σx parallel of the interface was always the and it can be inferred that fracture has taken place at largest within the joint, and in the free surface the interface of the Cu–Ti intermetallic layers and suddenly reduced to 0. In this work, a uniaxial spread to the TiC cermet layer. The presence of the compressive load of 2–10 MPa was applied along Ti–Cu IMCs and the fracture of TiC cermet lead to the longitudinal direction of sample in the process decreasing the strength of the bonded joint, of bonding which results in the compressive stress indicating that this is the weak point in the PTLP σy perpendicular to the interface by lateral bonded joint. contraction of the ceramic and steel [23]. The ZDANIEWSKI et al [23] and BLUGAN et al addition of Nb (7.2×10–6 K–1) and Ti (9.4×10–6 K–1) [24] revealed that the residual stresses were at should theoretically accommodate the mismatch

J. Cent. South Univ. (2018) 25: 1025–1032 1031

4 Conclusions

By utilizing impulse pressuring in combination of Ti/Cu/Nb interlayer, successful PTLP bonding of TiC cermet to commercially 06Cr19Ni10 SS can be achieved at 885 °C within duration of only 2–8 min under the bonding pressure of 2–10 MPa in vacuum. This technique provided a reliable and efficient diffusion bonding method of TiC cermet to stainless steel. 1) Adopting the PTLP bonding technique can shorten the bonding time notably. 2) The Ti–Cu–Nb interlayer can effectively promote the interdiffusion and reaction between TiC cermet and SS. The joints were characterized by the presence of the σ phase with a limited solubility of Nb, a sequence of Ti–Cu intermetallic phases and solid solutions of Ni and Cu in α+β Ti in the reaction zone, from SS to TiC side. 3) The maximum shear strength of 106.7 MPa can be achieved when the joints were bonded for 5 min. Upon shear loading, the fracture took place through the Ti–Cu IMCs interface to the interior of Figure 5 XRD patterns of fracture surface: (a) TiC TiC cermet in a typical brittle fracture manner. cermet side; (b) SS side

between TiC cermet (7.4×10–6 K–1) and SS References (12–13×10–6 K–1). The CTE values of new [1] LIU N, XU Y D, LI H. Effect of nano-micro TiN addition on generated α+β Ti phases and Ti Cu adjacent to TiC 2 the microstructure and mechanical properties of TiC based –6 –1 –6 cermet were (9.41–10.03)×10 K and 13.5×10 cermets [J]. J Eur Ceram Soc, 2002, 22(13): 2409–2414. –1 K respectively [6, 17]. Thus, the residual stresses [2] SUN K N, YIN Y S, LI A M. Intermetallics/ceramic matrix at TiC cermet/α+β Ti/Ti2Cu interface were composite [M]. Beijing: China , 2002. (in alleviated. However, there was still the weak region Chinese) in TiC cermet. In effect, the fracture was not only [3] TRAVESSA D, FERRANTE M, DEN O G. Diffusion bonding of oxide to stainless steel using stress based on the CTE values, but also determined by relief interlayers [J]. Mater Sci Eng A, 2002, 337(1): the plastic deformation of brazed interface [25]. The 287–296. ability of plastic deformation of brazed interface [4] SHEN X Q, LI Y J, PUTCHKOV U A. Finite-element was reflected by the hardness of new phases analysis of residual stresses in Al2O3–TiC/W18Cr4V diffusion indirectly because the low hardness corresponds to bonded joints [J]. Comp Mater Sci, 2009, 45(2): 407–410. relatively high plasticity and . It was [5] YE D M, XIONG W H. Vacuum brazing of Ti(C, N) based obvious that the TiC substrate with the highest cermets to 45 Steel [J]. Rare Metal Mat Eng, 2008, 37(7): 1281–1284. Vickers hardness (28–35 GPa) [6] has low fracture [6] PIERSON H O. Handbook of refractory carbides & nitrides: toughness due to its covalent nature. This indicated Properties, characteristics, processing and apps [M]. William that the ability of plastic deformation of TiC cermet Andrew, 1996. was weaker than that of other metal phases. [7] GOMEZ-DE-SALAZAR J M, BARRENA M I. Dissimilar Therefore, the fracture propagation was originated fusion welding of AA7020/MMC reinforced with Al2O3 in Ti–Cu IMCs interface, and then spreaded to the particles, microstructure and mechanical properties [J]. Mater Sci Eng A, 2003, 352(1): 162–168. TiC cermet in a typical brittle fracture manner, [8] BARRENA M I, GOMEZ-DE-SALAZAR J M, when exerting an external shear load upon the MATESANZ L. Ni–Cu alloy for diffusion bonding brazed joints. cermet/steel in air [J]. Mater Lett, 2009, 63(24): 2142–2145.

1032 J. Cent. South Univ. (2018) 25: 1025–1032 [9] LI Z R, FENG J C, CAO J. Vacuum diffusion bonding of diffusion bonding of Ti alloy/austenite stainless steel

TiB2 cermet to TiAl based alloys [J]. Mater Sci Tech-Lond, processed by surface self-nanocrystallization [J]. ISIJ Int, 2004, 20(12): 1666–1668. 2009, 49(1): 86–91. [10] HUANG W Q, LI Y, WANG J. Microstructure and fracture [19] SUN X J, GU J L, BAI B Z, CHEN N P. Fabrication of

of TiC-Al2O3/W18Cr4V diffusion bonded joint [J]. Kovove submicron grained titanium alloy by compressive Mater, 2010, 48: 227–231. deformation [J]. Acta Metall Sin-Engl, 2009, 13(2): [11] CHEN Z, CAO M S, ZHAO Q Z. Interfacial microstructure 638–644.

and strength of partial transient liquid-phase bonding of [20] LIU G M, ZOU G S, WU A P. Improvements of the Si3N4 silicon nitride with Ti/Ni multi-interlayer [J]. Mater Sci Eng brazed joints with intermetallics [J]. Mater Sci Eng A, 2006, A, 2004, 380(1): 394–401. 415(1): 213–218. [12] ZHENG C, LOU H, FEI Z. Partial transient liquid-phase [21] XU H, DU Y, HUANG B. Phase equilibria of the Cu–Nb–Ti

bonding of Si3N4 with Ti/Cu/Ni multi-interlayers [J]. J Mater system at 850 °C [J]. J Alloy Compd, 2005, 399(1): 92–95. Sci Lett, 1997, 16(24): 2026–2028. [22] KUNDU S, CHATTERJEE S. Characterization of diffusion [13] WANG G, LANNUTTI J J. Chemical thermodynamics as a bonded joint between titanium and 304 stainless steel using a predictive tool in the reactive metal brazing of ceramics [J]. Ni interlayer [J]. Mater Charact, 2008, 59(5): 631–637. Metall Mater Trans A, 1995, 26(6): 1499–1505. [23] ZDANIEWSKI W A, CONWAY J C, KIRCHNER H P. [14] MASSALSKI T B, OKAMOTO H, SUBRAMANIAN P R. Effect of joint thickness and residual stresses on the Binary alloy phase diagrams [M]. Materials Park, OH: ASM properties of ceramic adhesive joints: II, Experimental International, 1990. results [J]. J Am Ceram Soc, 1987, 70(2): 110–118. [15] YANG M, ZOU Z D, SONG S L. Effect of interlayer [24] BLUGAN G, KUEBLER J, BISSIG V. Brazing of silicon

thickness on strength and fracture of Si3N4 and Inconel600 nitride ceramic composite to steel using SiC-particle- joint [J]. Key Eng Mater, 2005, 297: 2435–2440. reinforced active brazing alloy [J]. Ceram Int, 2007, 33(6): [16] MARKS R A, SUGAR J D, GLAESER A M. Ceramic 1033–1039. joining IV. Effects of processing conditions on the properties [25] SINGH M, MARTINEZ F J, ASTHANA R. Interfacial of alumina joined via Cu/Nb/Cu interlayers [J]. J Mater Sci, characterization of silicon nitride/silicon nitride joints brazed 2001, 36(23): 5609–5624. using Cu-base active metal interlayers [J]. Ceram Int, 2012, [17] SHACKELFORD J F, ALEXANDER W. CRC materials 38(4): 2793–2802. science and engineering handbook [M]. CRC Press, 2010. (Edited by YANG Hua) [18] HAN J, SHENG G M, ZHOU X L. Pulse pressuring

中文导读

Ti/Cu/Nb 作中间层脉冲加压瞬间液相连接 TiC 金属陶瓷与不锈钢

摘要：部分瞬间液相焊接（PTLP）综合了钎焊和固相扩散连接的优点，且对连接母材表面粗糙度比 传统固相连接相对较低，因此在陶瓷和金属异种材料连接方向上具有较大的优势。采用 Ti–Cu–Nb 金 属中间层，对 TiC 金属陶瓷与 06Cr19Ni10 不锈钢进行 PTLP 连接试验。通过 SEM、EDS、XRD 和拉 伸试验等方法，研究了活性元素中间层、工艺参数对 TiC/TiCuNb/06Cr19Ni10 瞬间液相焊接头性能与 界面微观结构的影响规律。结果表明，在连接温度 885 °C、脉冲压力 2~10 MPa 的工艺条件下保温 5 min 时接头剪切强度达到最大值（~106.7 MPa）。微观组织表征发现，在 TiC 金属陶瓷一侧，Ti–Cu 层在高 于共晶点的连接温度时发生熔化，与 TiC 金属陶瓷、核心金属层 Nb 产生界面反应；而在 304SS 侧， Nb 与 304SS 进行固相扩散，形成具有固相扩散特征的连接结构，连接后界面形成

06Cr19Ni10/σ/Nb/CuTi/CuTi2/α+βTi/TiC 过渡结构。连接接头的裂纹沿着 Ti–Cu 金属化合物层向 TiC 陶 瓷母材扩展，呈脆性解理断裂特征。

关键词：TiC 金属陶瓷; 不锈钢; 瞬间液相连接；脉冲加压；断口；力学性能