Dislocation-Controlled Low-Temperature Superplastic Deformation of Ti-6Al-4V Alloy

Frontiers in Materials

Chao Liu¹  Xin Wang¹  Ge Zhou¹  Haoyu Zhang¹  Siqian Zhang¹  Lijia Chen¹  Feng Li¹  Haijian Liu² 

[1] School of Materials Science and Engineering, Shenyang University of Technology, Shenyang, China;Shanghai Spaceflight Precision Machinery Institute, Shanghai, China;

关键词: Ti-6Al-4V alloy;    low-temperature superplasticity;    strain rate sensitivity index m;    deformation mechanism map;    dislocation;   

DOI  :  10.3389/fmats.2020.606092

来源: DOAJ

【 摘 要 】

The superplastic tension and deformation mechanism of Ti-6Al-4V alloy at 923 K and a tensile speed of 10−3, 5 × 10−3, or 5 × 10−2 s−1 was studied on an AG 250KNE electronic tension tester. Through theoretical modeling, the unit dislocation count of this alloy during superplastic deformation was introduced into the Ruano–Wadsworth–Sherby (R-W-S) deformation mechanism map, and a new deformation mechanism map involving dislocation count was plotted. Thereby, the mechanism underling the low-temperature superplastic deformation of this alloy was predicted. It was found the superplastic tension of Ti-6Al-4V at the tested temperature was controlled by dislocation movement, and with an increase in strain rate, the deformation transited from the dislocation-controlled mechanism with a stress index of 4 to the dislocation glide mechanism with a stress index of 5 or 7. At the strain rate of 10−3 s−1, this alloy reached the largest tension rate of 790% and strain rate sensitivity index of 0.52 and had excellent low-temperature superplastic properties.

【 授权许可】

Unknown