共析钢的相变超塑性扩散连接

根据高温扩散和空洞蠕变闭合理论，在恒温超塑性扩散连接基础上建立相变超塑性扩散连接数学模型，可确定各工艺参数，诸如循环上限温度、压力、循环次数以及升、降温速率等对连接的影响，作为选择合适工艺参数的依据。经过对T8共析钢相变超塑性扩散连接试验研究，证明该理论模型与试验结果吻合较好。

Theoretical Model of Transformation Superplastic Diffusion Welding for Eutectoid Steel

Based on current theories of diffusion and creep cavity closure at high temperature, a theoretical model is established for bonding process of transformation superplastic diffusion welding(TSDW) on the basis of the theoretical model for isothermal superplastic diffusion. The bonding quality can be predicted which is affected by technological parameters, such as the limited cycle temperature, the compressive stress, the number of thermal cycles and the temperature cycling through the phase transformation in the thermal cycle, etc. Results show that the maximum temperature, the compressive stress, the number of thermal cycles and the rate of temperature rising speed in the thermal cycle have an important influence on the TSDW process. Meanwhile, reasonable technological parameters are chosen from the theoretical analysis which is in good agreement with experimental results.