CuSnTi复合钎料原位反应机制与接头组织性能

In-situ reaction mechanism and joint microstructure and properties of CuSnTi composite brazing material

简化CuSnTi钎料制备流程、降低生产成本对高性能工具的发展至关重要。本文通过直接机械混合Cu、Sn、Ti单质金属粉制备CuSnTi钎料,并用于钎焊PcBN/YG8异质材料,研究不同反应温度下CuSnTi钎料的微观组织演化,揭示钎焊过程中钎料的原位反应机制,并分析接头组织与性能。结果表明:CuSnTi钎料原位反应主要分为3个阶段:第一阶段,Sn熔化与Cu发生反应依次形成Cu_(6)Sn_(5)与Cu_(3)Sn;第二阶段,Ti颗粒周围依次形成CuTi、Cu_(4)Ti_(3)、CuTi_(3)与CuSn_(3)Ti_(5);第三阶段,液态钎料与石墨基体反应形成TiC,然后凝固析出不规则CuSn_(3)Ti_(5)。利用机械混合粉末钎料和合金粉钎料钎焊的PcBN/YG8接头均为冶金结合,其剪切强度分别为96.06 MPa和91.40 MPa。机械混合粉末钎料钎焊的接头在PcBN处发生断裂,具有优良的力学性能。

Simplifying the preparation process of CuSnTi solder and reducing production costs are crucial for the development of high-performance tools.In this paper,direct mechanical mixing technique of Cu,Sn,and Ti metal powders was employed to synthesize CuSnTi brazing materials,which was then used to brazed PcBN/YG8 heterogeneous materials.The evolution of microstructures of CuSnTi brazing materials at different reaction temperatures were studied,the in-situ reaction mechanism of brazing materials during the brazing process was revealed,and the microstructure and properties of joint were analyzed.The results show that the in-situ reaction of CuSnTi brazing material can be mainly divided into three stages:in the first stage,Sn melts and reacts with Cu to form Cu_(6)Sn_(5)and Cu_(3)Sn in sequence;in the second stage,CuTi,Cu_(4)Ti_(3),CuTi_(3),and CuSn_(3)Ti_(5)precipitate surrounding Ti particles in sequence;in the third stage,liquid brazing material reacts with graphite substrate leading to the formation of TiC,and then solidification and precipitation of irregular CuSn_(3)Ti_(5).PcBN/YG8joints brazed with mechanical mixed powder brazing material and alloy powder brazing material both have good metallurgical bonding,with shear strengths of 96.06 MPa and 91.40 MPa,respectively.The joint brazed with mechanical mixed powder brazing material breaks at the PcBN site and exhibits excellent mechanical properties.