固溶时效处理对Ti-0.3Mo-0.8Ni钛合金微观组织与力学性能的影响

Effect of Solution and Aging Treatment on Microstructure and Mechanical Properties of Ti-0.3Mo-0.8Ni Titanium Alloy

对Ti-0.3Mo-0.8Ni钛合金进行固溶时效处理,采用光学显微镜、室温拉伸测试以及扫描电子显微镜,研究Ti-0.3Mo-0.8Ni钛合金经不同固溶时效温度处理后的微观组织与力学性能。结果表明:随固溶温度的升高,合金组织中初生α相含量不断减少直至消失,同时有大量次生α相析出,合金组织类型由双态组织逐渐转变为细片层组织。合金塑性随固溶温度升高而逐渐降低,而强度变化趋势与塑性相反。固溶温度为两相区时,合金的拉伸断口形貌主要由大量韧窝构成,且有少量的二次裂纹及孔洞;当固溶温度为单相区时,合金的拉伸断口形貌主要由结晶状形貌构成,出现解理台阶及撕裂棱,并有少量细小的韧窝在断口表面分布。

Solid solution aging treatment was performed on Ti-0.3Mo-0.8Ni titanium alloy,and then the microstructure and mechanical properties of the treated Ti-0.3Mo-0.8Ni alloy were studied through the optical microscope imaging,room temperature tensile test,and scanning electron microscopy characterization.The results show that the content of primaryαphase decreased and even disappeared with the increase of solution temperature,and meanwhile,a large amount of secondaryαphase precipitated.The microstructure type of the alloy gradually changed from the bimodal structure to the fine lamellar structure.The plasticity of the alloy decreases gradually with the increase of solution temperature,while the strength shows the opposite trend with plasticity.When the solid solution temperature is in the two-phase region,there are a large number of ductile dimples,and a small number of secondary cracks and voids on the tensile fracture surface.When the solid solution temperature is in the single-phase region,the tensile fracture has the crystalline morphology with cleavage steps and tearing edges,and a small number of tiny dimples are distributed on the fracture surface.