固溶温度对Ti-1300合金时效析出行为与性能的影响

研究了Ti-1300合金固溶处理后低速率升温时效的α相析出行为及力学性能。通过SEM、TEM和拉伸试验等手段对不同固溶温度处理的Ti-1300合金进行显微组织观察和力学性能测试。结果表明:随着固溶温度由820 ℃降低至790 ℃,初生α相(α_p)的尺寸变化不明显,但是其含量(面积分数)从0.8%增至6.7%;合金经4 ℃/min升温速率加热到500 ℃时效4 h,显微组织中析出次生α相(α_s)的长度从0.098 μm 增加到0.440 μm。此外,固溶温度降低使合金的强度与塑性均提高,拉伸断口由沿晶脆性断裂特征转变为韧窝状的韧性断裂特征。820 ℃固溶处理的试样其抗拉强度为1358 MPa,断后伸长率小于2%,而790 ℃固溶处理的试样其抗拉强度为1548 MPa,断后伸长率为10.2%,可获得优良的强塑性匹配。分析认为790 ℃固溶处理组织中初生α相含量较多,其尺寸为微米尺度,同时基体中时效析出的片层α_s相能产生显著的强化效果。

Effect of solid solution temperature on aging precipitation behavior and properties of Ti-1300 alloy

Precipitation behavior of α phase and mechanical properties of Ti-1300 alloy after solution treatment followed by aging with low heating rate were investigated.The microstructure and mechanical properties of the Ti-1300 alloy with different solution treatment temperatures were observed and tested by means of SEM,TEM and tensile testing.The results show that when the solid solution treatment temperature is decreased from 820 ℃ to 790 ℃,the size of α_p (primary α phase) changes a little,while the area fraction of α_p increases from 0.8% to 6.7%.Subsequently,aging at 500 ℃ for 4 h with the heating rate of 4 ℃/min results in that the length of α_s (secondary α phase) increases from 0.098 μm to 0.440 μm.In addition,the decrease of solution treatment temperature increases the strengh and platisity of the alloy,and resulting in that the tensile fracture changes from intergranular brittle fracture to dimple-type ductile fracture.The tensile strength of the specimen solution-treated at 820 ℃ is 1358 MPa with platisity below 2%.While solution treated at 790 ℃,an excellent combination of strenth (1548 MPa) with platisity (10.2%) is obtained,the main reason of which is the high content of primary α phase in micrometer scale,and the lamella-shaped α_s precipitated in the matrix has significant strengthening effect.