High Temperature Deformation Behavior of In-Situ Synthesized Titanium-Based Composite Reinforced with Ultra-Fine TiB Whiskers

• Main Authors: Rongjun Xu, Bin Liu, Yong Liu, Yuankui Cao, Wenmin Guo, Yan Nie, Shifeng Liu
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Materials
• Subjects: titanium based composites; hot deformation; processing map; ultra-fine TiB; powder metallurgy
• Online Access: http://www.mdpi.com/1996-1944/11/10/1863

A TiB/Ti-6Al-4V composite reinforced with ultra-fine TiB whiskers (UF-TiB) was prepared by the powder metallurgy method. High temperature compression tests were carried out to study the hot deformation behavior of the UF-TiB/Ti-6Al-4V composite. The compressive deformation was performed in the temperature range of 900–1200 °C and the strain rate range of 0.001–10 s−1. The results showed that stable flow occurred at the condition of 900–1200 °C/0.001–0.01 s−1. The optimum working condition was 900 °C/0.001 s−1, with the deformation mechanism of dynamic recrystallization (DRX). Instable flow occurred when the strain rate was higher than 0.01 s−1, where the failure modes included adiabatic shear deformation, whisker breakage and whisker/matrix debonding. The deformability of the UF-TiB/Ti-6Al-4V composite was much better than the traditional casted and the pressed + sintered TiB/Ti-6Al-4V composites, which are typically reinforced with coarse-grained TiB whiskers. The high deformability was primarily attributed to the ultra-fine reinforcements, which could coordinate the deformation more effectively. In addition, a fine matrix microstructure also had a positive effect on deformability because the fine matrix microstructure could improve the grain boundary sliding.