High-temperature Compressive Properties and Microstructural Evolution with Different Solution Temperatures and Cooling Rates for the Ti60 Alloy
摘要
This study examines the effects of solution treatment temperatures (1045 ℃, 1030 ℃, 1015 ℃, 1000 ℃ and 985 °C) and cooling methods (WQ, OQ, AC, FC, OFC) on the high-temperature compressive properties of Ti60. The results show that lower cooling rates reduced high-angle grain boundaries, increased average grain size, and suppressed dynamic recrystallization. Solution temperature regulates β-grain size and Mo content in the β phase: in the β single-phase region, β grains coarsen significantly, while in the α + β phase region, finer equiaxed grains and higher Mo content in β phase are retained. In high-temperature compression, Ti60 alloy exhibits distinct dual-yield behavior, attributed to the competitive interplay between DRX initiation and dislocation-driven deformation, which is absent in high-temperature tension. The more uniform triaxial stress distribution under compressive loading leads to a significantly higher strain hardening rate in compression than in tension. When the solution temperature is ≥ 1030 °C, the compressive yield strength of the material is higher than the tensile yield strength, whereas when the temperature is < 1030 °C, this trend is reversed. Using Response Surface Methodology, 1045 °C solution treatment with 1367 °C/min cooling was identified as the optimal condition, yielding a CYS of 669.13 MPa, a strain hardening exponent n of 0.9325, and an energy dissipation density W of 5.051 × 104 kJ/m3.
Graphical abstract