Effects of solution temperature and cooling rate on microstructure and micro-hardness of a hot compressed Ti-6Al-4V alloy. (January 2019)

• Record Type: Journal Article
• Authors: Lin, Y.C.; Tang, Yi; Zhang, Xiao-Yong; Chen, Chao; Yang, Hui; Zhou, Ke-Chao
• Is Part Of: Vacuum. Volume 159(2019)
• Page Start: 191
• Page End: 199
• Publication Date: 2019-01
• Subjects: Alloy -- Solution temperature -- Cooling rate -- Microstructure -- Micro-hardness; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2018.10.035
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: The effects of solution temperature and cooling rate on microstructure and micro-hardness of a hot compressed Ti-6Al-4V alloy are investigated. The microstructure observations reveal the occurrence of static recrystallization during solution treatment. The lamellar α phases firstly decompose into the short-rod phases, and then gradually spheroidize. The increased solution temperature can accelerate the transformation of α grain boundary from the low-angle grain boundaries (LAGB) to the high-angle grain boundaries (HAGB). So, the growth and spheroidization of α grains become more and more obvious. Meanwhile, the precipitation of secondary α phases is promoted. The micro-hardness is significantly improved after the solution treatment, i.e., the micro-hardness undergoes the rapid decrease and slow increase with raising the solution temperature. In addition, the cooling rate has great impact on the microstructures and micro-hardness. With reducing the cooling rate, the mean size of equiaxed α grains and the thickness of lamellar α phases obviously increase. Highlights: Effects of post-deformation heat treatment on microstructures and micro-hardness of Ti-6Al-4V alloy are studied. Lamellar α phases firstly decompose into the short-rod phases, and then gradually spheroidize. The increased solution temperature accelerates the transformation of α grain boundary from LAGB to HAGB. Micro-hardness undergoes the rapid decreases and slow increase with the increase of solution temperature. The mean size of equiaxed α grains and the thickness of lamellar α phases increase with reducing cooling rate.