固溶处理对TC11钛合金组织与性能的影响

通过光学显微镜、扫描电镜、X射线衍射仪以及室温拉伸性能测试，研究TC11钛合金分别在955、975、995和1015℃固溶处理后的微观组织与力学性能的对应关系。结果表明，合金原始锻态显微组织为α+β两相区锻造形成的双态组织，以α_p相和β转变组织为主。经固溶处理后，原始锻态组织中被扭转和拉长的α_p相随着固溶温度升高逐渐变小、变圆，同时体积较小的α_p相逐渐消失。固溶温度为995℃时，合金强度达到最大值，抗拉强度(R_m)为1403 MPa,屈服强度(R_p0.2)为1158 MPa;固溶温度为955℃时，合金塑性最佳，断后伸长率(A)为9.5%,断面收缩率(Z)为32%。当固溶温度位于两相区时，其拉伸断口微观形貌相似，均以韧窝为主；当固溶温度位于单相区时，断口形貌结晶状明显，且有较大的撕裂棱，在岩石状表面有大量撕裂状小韧窝。

Effect of solution treatment on microstructure and properties of TC11 titanium alloy

Relationship between microstructure and mechanical properties of the TC11 titanium alloy after solution treatment at 955, 975, 995 and 1015 ℃, respectively, was studied by means of optical microscope, scanning electron microscope, X-ray diffraction and room temperature tensile test. The results show that the original as-forged microstructure of the alloy is a bimodal structure formed by forging in the α+β two-phase region, which is dominated by α_p phase and β transformation structure. After solution treatment, the twisted and elongated α_p phase in the original as-forged structure gradually becomes smaller and rounded with the increase of solution treatment temperature, and the smaller α_p phase gradually disappears. When the solution treatment temperature is 995 ℃, the strengths of the alloy reach the maximum, of which the tensile strength (R_m) is 1403 MPa and the yield strength (R_p0.2) is 1158 MPa. When the solution treatment temperature is 955 ℃, the plasticity of the alloy is the best, of which the elongation after fracture (A) is 9.5% and the percentage reduction of area (Z) is 32%. When the solution treatment temperature is in the two-phase region, the tensile fracture morphology is similar, which is mainly dimples. When the solution treatment temperature is in the single-phase region, the fracture morphology is obviously crystalline and has large tearing edges, and there are a large number of small tearing dimples on the rock-like surface.