最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Abstract: In this study, powder metallurgy (PM) Ti6Al4V alloy was forged in different ways. The properties and microstructure of the alloy before and after forging were also analyzed. The results showed that forging was an effective way to improve the density and mechanical properties of PM titanium alloys. Firstly, the PM Ti6Al4V alloy was performed a once forging deformation at different temperatures. The alloy forged at 960℃ had better ductility with an elongation of 15.44%. With the increasing of forging temperature, the equiaxial α phases decreased, and gradually changed to the basket weave structure, resulting in the plasticity decreasing. However, due to the inhibition of the original powder particle boundary on grain growth, there was no obvious grain growth in the alloy forged at 1150℃. The grain smaller than 20??m accounted for about 71%. As fine grain size was beneficial to the plasticity, the elongation still reached to 14.3%. Therefore, the PM Ti6Al4V alloy had a wider forging temperature window compared to the traditional cast titanium alloy. Besides, the PM Ti6Al4V alloy was performed a twice forging deformation at different temperature. In such case, the alloy was firstly forged at high temperature to improve the density with small deformation, and then was forged at lower temperature to obtain the required microstructure. The Ti6Al4V alloy with twice forging deformation had an elongation of higher than 17%, tensile strength of higher than 990MPa, and yield strength of higher than 960MPa.