The microstructural features of high-temperature titanium alloy Ti650 and their effects on mechanical properties were investigated. Results indicate that the S2-type (Ti,Zr)6Si3 silicide precipitates in the alloy exhibit no specific crystallographic orientation relationship with the matrix. Their morphology and distribution strongly depend on the microstructure type: in fine-lamellar Widmanst?tten structure, fine elliptical particles (20–60 nm) precipitate along the α/β interface; while in equiaxed, dual-phase, or coarse-lamellar Widmanst?tten structures, blocky silicides (approximately 200 nm) form within α grains. Room-temperature tensile tests reveal that equiaxed and dual-phase microstructures achieve the optimal strength-ductility balance (tensile strength of approximately 1100 MPa, elongation of approximately 13%). The fine-lamellar structure exhibits outstanding creep resistance at 650 °C and 100 MPa, with a steady-state creep rate nearly one order of magnitude lower than that of the equiaxed structure. Further mechanism analysis indicates that in the equiaxed structure, dislocations can traverse coarse silicide grains within the crystal via bypass mechanisms, allowing the creep process to persist. In contrast, fine spherical silicides are uniformly distributed within the lamellae and at grain boundaries. These silicides synergistically strengthen the lamellar structure, significantly increasing the energy barrier to dislocation motion and thereby conferring superior creep resistance on this microstructure.
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周伟,洪权,王晓,辛社伟,赵圣泽,侯红苗,杨海瑛,闫康.组织形态对高温钛合金Ti650典型力学性能的影响[J].稀有金属材料与工程,2026,55(10):2484~2490.[Zhou Wei, Hong Quan, Wang Xiao, Xin Shewei, Zhao Shengze, Hou Hongmiao, Yang Haiying, Yan Kang. Effect of Microstructure on Typical Mechanical Properties of High-Temperature Titanium Alloy Ti650[J]. Rare Metal Materials and Engineering,2026,55(10):2484~2490.] DOI:10.12442/j. issn.1002-185X.20250600