Microstructure and mechanical properties of Al2O3 ceramic and Ti2AlNb alloy joints brazed with Al2O3 particles reinforced Ag-Cu filler metal
Microstructure and mechanical properties of Al2O3 ceramic and Ti2AlNb alloy joints brazed with Al2O3 particles reinforced Ag-Cu filler metal
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DOI：
10.1016/j.vacuum.2021.110430
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发表时间：
2021-07-07
期刊：
影响因子：
4
通讯作者：
Xiong, Jiangtao
中科院分区：
文献类型：
--
作者：
Peng, Yu;Li, Jinglong;Xiong, Jiangtao
采用微米级Al 2 O3颗粒改性AgCu 28钎料对Al 2 O3陶瓷与Ti 2AlNb合金进行钎焊。研究了Al 2 O3颗粒浓度对Al 2 O3/Ti 2AlNb接头组织和力学性能的影响。Ti-3（Cu，Al）（3）O是Al 2 O3-钎料界面反应的主要产物。Al 2 O3颗粒的加入显著降低了Al 2 O3陶瓷和Ti 2AlNb合金基体之间的热膨胀系数失配，缓解了接头的残余应力。然而，高浓度的Al 2 O3颗粒导致过量的具有高弹性模量的Ti 3Cu 3 O相包围Al 2 O3颗粒，这削弱了钎焊梁的塑性变形能力，从而降低了接头强度。当使用AgCu 28 + 2wt%Al2O3颗粒钎料在880 ℃下钎焊10 min时，接头的最大剪切强度为110.49 MPa。断口形貌分析表明，裂纹萌生于钎缝处，裂纹主要在Al 2 O3陶瓷基体上扩展。
This study focuses on the brazing of Al2O3 ceramic to Ti2AlNb alloy using composite filler metal (AgCu28 modified with micron-scale Al2O3 particles). The effect of Al2O3 particles concentration on the microstructure and mechanical properties of Al2O3/Ti2AlNb joint were investigated. Ti-3(Cu, Al)(3)O has been identified as the main product of the reactions at the alumina-brazing alloy interface. The addition of Al2O3 particles significantly reduced the mismatch of coefficients of thermal expansion between Al2O3 ceramic and Ti2AlNb alloy substrates, relieving the residual stresses of the joint. Nevertheless, a high concentration of Al2O3 particles led to excessive Ti3Cu3O phase exhibiting high elasticity modulus surrounded Al2O3 particles which impaired the plastic deformation ability of the brazing beam, thus, decreased the joint strength. The maximum shear strength of 110.49 MPa was achieved when the joint was brazed at 880 degrees C for 10 min using AgCu28 + 2 wt % Al2O3 particles filler metal. The fracture morphology revealed that the cracks initiated in the brazing seam, and mainly indicating the propagation of cracks occurred in the Al2O3 ceramic substrate.