热机械处理对β钛合金组织性能的影响

Effects of thermomechanical treatment on microstructure and mechanical properties of β titanium alloy

系统研究了不同变形状态（锻造φ38 mm和热轧φ17 mm、φ13 mm）及固溶冷却方式（水冷、空冷）对新型β钛合金固溶＋时效热处理显微组织及力学性能的影响。结果表明：锻态合金变形量小,固溶时效处理后次生α析出相较轧态合金的细小致密,析出相体积分数更高,因此强度比轧态高90 MPa。固溶水冷＋时效合金因其冷却速度较空冷快,晶界更清晰、晶内干净,但存在析出不均匀现象,固溶后冷却方式（水冷或空冷）对热轧态合金强度影响不显著。研究固溶冷却方式的影响时应综合考虑试样尺寸和合金元素含量的影响。

Effects of different deformation station（ forging to φ38 mm and hot rolling to φ17 mm,φ13 mm） and solid solution cooling methods（ water cooling,air cooling） on microstructure and mechanical properties of a new β titanium alloy were studied.The results indicate that the deformation of forged alloy is small,the secondary precipitation α phase（ αs） after solution aging treatment is smaller than that of rolled alloy,and the volume fraction of precipitated phase is higher,so the strength is 90 MPa higher than that of rolled state.As the cooling rate of the solid solution water-cooling ＋ aging alloy is faster than that of air cooling,the grain boundary is clearer and inside the grain is clean,but the distribution of precipitates is not uniform,but the influence of solid solution cooling（ AC or WC） on the hot rolling alloy strengths is not remarkable.The influence of sample size and alloy element content should be taken into consideration when studying the effects of solution cooling methods.