Al-12.7Si-0.7Mg合金超塑性变形行为及变形机理

对Al-12.7Si-0.7Mg合金在Instron5500电子万能材料试验机上进行超塑性拉伸实验.通过对该合金超塑性过程中延伸率δ,应变速率敏感性指数m值的计算,获得了不同变形温度、不同应变速率下δ和m值的变化规律.该合金在温度为793 K,应变速率为1.67×10-4s-1时,合金的应变速率敏感性指数和延伸率均达到最大值,分别为0.44,379%.分别构建了该合金的功率耗散率图以及铝合金RWS变形机理图.运用功率耗散率图预报该合金的超塑性变形区域;应用铝合金变形机理图并结合该合金超塑性拉伸前后显微组织变化规律,根据不同温度下Al-12.7Si-0.7Mg合金柏氏矢量补偿的晶粒尺寸值、模量补...

Superplastic Behavior and Deformation Mechanisms of Al-12.7Si-0.7Mg Alloy

Superplastic tensile deformation tests of Al-12.7Si-0.7Mg alloy were performed on Instron5500 electronic universal material testing machine.The variations of elongation(δ) and strain rate sensitivity exponent(m) at different strain rates and different temperatures were obtained.The results showed that the strain rate sensitivity exponent and elongation reach up to 0.44 and 379%,respectively,at a temperature of 793 K and the strain rate of 1.67×10-4 s-1.The deformation mechanism map inside grains and power dissipation rate map were obtained.The power dissipation rate map was used to predict the processing regime of superplastic deformation.Within the appropriate processing regime,based on the deformation mechanism maps,Burgers vector compensated grain size and modulus compensated stress of Al-12.7Si-0.7Mg alloy at different temperatures were calculated to elucidate the superplastic deformation mechanism.