加Sn对AgInCd压缩蠕变行为影响

Effect of Sn on Compressive Creep Behavior of AgInCd

采用现有RDL-50型拉伸蠕变试验机,改装部分试验装置后研究Ag In Cd合金加Sn前后在300~400℃温度及12~30 MPa应力范围内的压缩蠕变行为。根据试验结果详细分析稳态速率与温度、应力的关系,计算应力指数n和蠕变激活能Qa;并根据透射电子显微镜结果探讨合金的压缩蠕变机制。结果表明：随温度和应力水平的升高,合金的稳态蠕变速率增加。加Sn后,Ag In Cd对应力敏感性更大,且在任一应力下激活能更高,其抗蠕变性能较好。根据计算,300、350、400℃条件下,加Sn与不加Sn合金的蠕变应力指数n分别为9.41、8.07、9.48和3.31、4.10、5.77;12、18、24 MPa条件下,加Sn与不加Sn合金的蠕变激活能Qa分别为147.9、126.9、149.9 k J/mol和68.1、103.7、131.6 k J/mol。微观形貌以层错为主,300℃的主要蠕变机制为孪生,400℃的主要蠕变机制为位错攀移生成位错墙。

The Compressive creep behavior of as-cast AglnCd alloy with and without tin （Sn, 3 wt%） was investigated by using the special modified apparatus on RDL50 creep tester at 300-400℃ and compressive stress was in the range of 12-30 MPa.The relationship among temperature, stress and steady strain rate has been analyzed, the stress exponent n and apparent activation energy Q, of the creep process have been calculated as well as the mechanism of compressive creep behavior have been discussed, based on the TEM images of microstructure. The results showed that, the steady strain rate of the alloy increased with the increasing of temperature and compressive stress. Compared with AglnCd, the stress sensitivity became more obvious and Qa increased in each stress with the tin in it, indicating that the creep resistance of AglnCdSn was better. The n of AglnCd were 3.31, 4.09 and 5.77 under the 300℃, 350℃, 400℃ respectively, while of AglnCdSn were 9.41, 8.07 and 9.48. The Qa of AglnCd were 68.1, 103.7, 131.6 kJ/mol under 12, 18, 24 MPa, for AglnCdSn, namely 147.9, 126.9, 149.9 kJ/mol. There were lots of stacking faults in the TEM images under each creep condition, which played a critical role in the creep mechanism. Mechanical twinning was the main mechanism at 300℃ while dislocation climbing was the dominant mechanism at 400℃.