6Sn5層的生長，等溫時(shí)效期間金屬間化合物（Cu6Sn5+Cu3Sn）的生長為擴(kuò)散控制機(jī)制。焊接時(shí)形成的扇貝狀表面在時(shí)效時(shí)消失，這表明在垂直于界面方向上的生長機(jī)制變?yōu)榉€(wěn)定性增長，說明Ag3Sn有效降低了Cu6Sn5的生長動(dòng)力。;The interfacial reactions and growth kinetics of Sn-20Bi-0.7Cu-xAg (x=0.1, 0.4, 0.7, 1.0, 1.5, wt%) were investigated during solid-state aging. The effects of chemical composition on the structure and the growth of interface under high temperature and high humidity conditions were studied experimentally and numerically. In order to determine the long-term reliability of the solder joints, thermal accelerated aging tests were performed for 0, 10, 30, 50, 100, 200 and 500 h under 85 °C and 85% relative humidity conditions. The surface morphology, thickness, and distribution of interface compounds were observed by scanning electron microscope. The nucleation surface and growth direction of β-Sn were clarified. The phases were determined at the interface and the alloy matrix. Results show that with increasing the Ag content, the growth of the Cu6Sn5 layer is suppressed. The growth kinetics of intermetallic compound (Cu6Sn5+Cu3Sn) remains a diffusion-controlled process during the isothermal aging. The scallop-type Cu6Sn5 phase disappears at later aging stages, suggesting that the growth mechanism changes to the steady growth in the direction perpendicular to the interface. Besides, the results reveal that Ag3Sn effectively slows down the growth kinetics of Cu6Sn5."/>