A microstructure with improved thermal stability and creep resistance in a novel near-alpha titanium alloy

作者：Wang, Tongbo; Li, Bolong^*; Wang, Zhenqiang; Nie, Zuoren^*

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2018, 731: 12-20.

DOI：10.1016/j.msea.2018.06.034

• High-temperature titanium alloy
• Microstructure
• Creep resistance
• Thermal stability

A triple-microstructure with the precipitation of silicide along the alpha/beta phase boundaries and a 2 phase in the Ti-5.8A1-3Sn-5Zr-0.5Mo-1.0Nb-1.0Ta-0.4Si-0.2Er alloy was prepared for improving thermal stability and creep resistance. The alloys were forged at 1050 degrees C and 1000 degrees C followed by solution treatment at 1000 degrees C for 1 h and subsequent ageing at 700 degrees C for 5 h. The effects of a morphology and precipitation characteristics on the thermal stability and creep performance of high-temperature titanium alloy were investigated. A triple-microstructure with the participation of silicide along the alpha/beta phase boundary and a 2 phase was a promising structure with improved thermal stability and creep resistance. The plasticity loss rate was 25.0% after thermal exposure at 650 degrees C for 100 h due to the participation and coarsening of a 2 and silicide. Meanwhile, the plastic creep strain was 0.111% during the creep deformation at 650 degrees C for 100 h with an applied stress of 100 MPa, which was attributed to the inhibition of silicide and alpha(2) phase for boundary migration and dislocation slipping. Furthermore, the mutual precipitation of coarsening silicide and a alpha(2) phase inside a matrix was alpha significant reason for the dramatic decrease in the thermal ability, which also worsened the inhibition for dislocation climbing of silicon element during the creep deformation.

• 出版日期2018-7-25
• 单位北京工业大学