(北京有色金属研究总院 有色金属材料制备加工国家重点实验室，北京 100088)
摘 要: 研究不同冷却速度(水冷、空冷和炉冷)对VST55531合金的显微组织和拉伸性能的影响。结果表明：合金分别经820 ℃和900 ℃固溶处理及580 ℃时效后，其强度随冷却速度的减小而逐渐降低，塑性逐渐升高。合金在900 ℃固溶的组织为粗大b晶粒的魏氏组织，其固溶水冷和空冷及时效后获得的强度最高，达到1 400 MPa。合金经820 ℃固溶及时效后，获得双态组织，且塑性较好；经820 ℃，1 h固溶空冷和580 ℃，4 h时效的合金，具有较高的强度和较好的塑性匹配。
关键字: VST55531钛合金；冷却速度；强度；塑性
（State Key Laboratory for Fabrication Processing of Nonferrous Metals,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The microstructures and tensile properties of VST55531 alloys with different cooling rates were studied，including water cooling, air cooling and furnace cooling. The results show that when the cooling rate gets slower, the strength decreases while the plasticity increases. When the alloy is solution treated at 900 ℃ and then aged, the main microstructure is Widmanstatten with coarse β grain and the strength can reach 1 400 MPa with water cooling and air cooling methods. When the alloy is solution treated at 820 ℃ and then aged, the microstructure is bi-modal with good plasticity. The alloy has better balance of strength and plasticity under aging treatment of 820 ℃, 1 h solution (air cooling) and 580 ℃, 4 h.
Key words: VST55531 titanium alloy; cooling rate; strength; plasticity
