热处理温度对TC4薄板超塑性的影响

Influence of heat treatment temperature on superplasticity of TC4 sheet

本文通过采用细化晶粒、增加高温相比例的方法对用于低温超塑的TC4合金薄板材的超塑性进行了研究。结果表明:在板材加工时采用低温轧制,会增加变形体内的畸变能,提高α和β晶粒的再结晶形核率;变形后720~750℃再结晶退火使α相进一步球化,最终形成两相比例差较大的、均匀细小的等轴α+β组织,经测定α晶粒直径为2~5μm,其高温持久真应变应力0.2%的数值低于31MPa。

The superplasticity of TC4 titanium sheet with low temperature was invested by grain refiner and increase of the amount of high temperature phase. The results showed that low temperature rolling during the sheet machining could increase the distortion energy in the deformed body and improve the recrystallization nucleating rate of α + β grains. After deformation,αphases were further spheroidized under the condition of recrystallization annealing temperature of 720 ~ 750℃,and uniform and equiaxed α + β structure with a elective large differential ratio between α and β phase was finally deformed. According to the mensuration,the grain diameter was between 2 and 5μm,and 0. 2% true strain at high temperature was lower than 31 MPa.