循环温度场作用下空冷态TC4合金的拉伸性能和显微组织的变化

TENSILE PROPERTIES AND CHANGE IN MICROSTRUCTURE OF AIR COOLED TC4 ALLOY SUBJECTED TO CYCLIC TEMPERATURE FIELD

对１０２０、９５０和９００℃空冷的ＴＣ４合金在－１９６～３５０℃间进行了热循环试验，测定了热循环前后的拉伸性能。结果表明：经１０００次热循环后强度上升，塑性下降，合金中的位错密度增大，形变孪晶的数量增多，其中９５０℃空冷合金的强度上升幅度最大。

The thermal cycling tests between -196 and 350 ℃ were performed on the TC4 alloy air cooled from 1 020, 950 and 900 ℃. The tensile properties before and after thermal cycling were evaluated. Experimental results show that after 1 000 thermal cycles, the strength increases, the ductility decreases and the dislocation density or amount of deformation twins increase, among which the specimens air cooled from 950 ℃ have the largest increase in strength and have the largest residual ductility.