Hot Deformation Behavior and Microstructure Evolution of a TiBw/Near α-Ti Composite with Fine Matrix Microstructure

Metals

Shuzhi Zhang¹  Hong Feng¹  Yuzhou Lian¹  Changjiang Zhang¹  Yonggang Sun¹  Peng Cao²  Yawei Zhou³  Yanfei Chen³ 

[1] College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;Department of Chemical and Materials Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand;Inner Mongolia Metallic Materials Research Institute, Ningbo 315103, China;

关键词: titanium matrix composites;    hot deformation behavior;    microstructure evolution;    processing map;   

DOI  :  10.3390/met9040481

来源: DOAJ

【 摘 要 】

The hot deformation behavior and microstructure evolution of a 7.5 vol.% TiB_w/near α-Ti composite with fine matrix microstructure were investigated under the deformation conditions in a temperature range of 800−950 °C and strain rate range of 0.001−1 s⁻¹ using plane strain compression tests. The flow stress curves show different characteristics according to the various deformation conditions. At a higher strain rate (1 s⁻¹), the flow stress of the composite continuously increases until a peak value is reached. The activation energy is 410.40 kJ/mol, much lower than the activation energy of as-sintered or as-forged composites. The decreased activation energy is ascribed to the breaking of the TiB_w reinforcement during the multi-directional forging and the resultant fine matrix microstructure. Refined reinforcement and refined matrix microstructure significantly improve the hot deformation ability of the composite. The deformation conditions determine the morphology and fraction of α and β phases. At 800−900 °C and 0.01 s⁻¹ the matrix α grains are much refined due to the continuous dynamic recrystallization (CDRX). The processing map is constructed based on the hot deformation behavior and microstructure evolution. The optimal hot processing window is determined to be 800−950 °C/0.001−0.01 s⁻¹, which lead to CDRX of primary α grains or dynamic recovery (DRV) and dynamic recrystallization (DRX) of β phase.

【 授权许可】

Unknown