超塑变形对TC4室温力学性能的影响

Influence of Superplastic Forming on the Room Temperature Mechanical Properties of TC4 Alloy

在T=880℃和.ε=9.8×10-4s-1下,进行了TC4圆筒件超塑成形试验,研究了超塑变形量对TC4室温强度、疲劳性能和金相组织的影响。结果表明:随着变形量的增加,晶粒尺寸增大。当超塑胀形延伸率e为55%时,晶粒尺寸由供应态的约8μm增加为约20μm。随着e增加,TC4室温下的屈服强度、抗拉强度和条件疲劳强度降低。当e为55%时,材料的屈服强度、抗拉强度下降约7%;循环周期为106下的疲劳强度下降约10%。

Superplastic forming （SPF） of a TC4 alloy cylinder at 880℃ and strain rate ε=9.8×10-4s-1 were conducted. The influences of superplastic deformation on room temperature strength,fatigue strength and metallurgical structure of TC4 alloy were investigated. Results show that grain size grows with SPF elongation increasing.. Grain size increases to about 20 μm from the initial dimension about 8 μm as SPF elongation equals to 55 %. At room tem- perature, yield strength, tensile strength and fatigue strength of TC4 alloy decrease with the increasing of SPF elonga- tion. After TC4 alloy sheet subjected to a SPF elongation of 55%, the yield strength and tensile strength reduce 7% ： the fatigue strength reduces 10% at the fatigue life cycle of 106.