Effects of Ga on Mechanical Properties and Microstructure of Cu–Sn–Ti Filler

To solve a series of problems of Cu–Sn–Ti fillers, Ga is added to the fillers to promote its mechanical properties and microstructure. The metallographic structure of Cu–Sn–Ti–xGa filler metals is detected by optical microscope. Energy dispersive spectroscopy (EDS) areal, X‐ray diffraction (XRD), and differential thermal analysis (DSC) are used to analyze the morphology and microstructure of the fillers. The results show that doped Ga can significantly decrease the melting point and increase mechanical properties of the fillers. The shear strength of the filler metals with 1% Ga content is 160% higher than without Ga. In addition, it is also observed that a small amount of Ga refine the CuSnTi filler metals matrix structure. The diffusion of elements in the filler metals is detected. Compared with Sn solid solution, Ga tends to form a solid solution with Cu. When the Ga content is 2 wt%, the shear strength of the filler metal decreases due to the appearance of coarse crystals at the bottom of the dimple. Through the study of the reaction layer between diamond and filler metal, it is found that Ga can increase the thickness of the interface reaction layer.