时效处理对近β型钛合金TLM组织与性能的影响

Effect of Aging Treatment on Microstructure and Mechanical Properties of Near Beta Type Titanium Alloy TLM

研究了不同时效温度和保温时间对近β型钛合金TLM微观组织和力学性能的影响。结果表明,经β单相区固溶+时效处理后合金微观组织特征为:沉淀α相在晶界两侧沿一定的晶体学位向呈集束状析出,晶内也有大量沉淀α相产生。随着时效温度升高,沉淀α相尺寸逐渐增大且趋于均匀,合金强度降低,塑性增强。当时效温度从480℃升高至510℃时,强化效果最为明显,合金的抗拉强度增量达到最大值184 MPa;当时效温度从510℃升高至540℃时,抗拉强度增量最小,仅63 MPa。随着保温时间的延长,晶界附近析出的集束状α相尺寸明显增大,且在原来未析出区域也有α相产生,分布逐渐趋于均匀。在480℃下进行时效时,随着保温时间增加,合金强度增大,塑性降低;在510℃下进行时效时,合金强度和塑性随保温时间延长变化不明显;在540℃下进行时效时,随着保温时间增加,合金强度减小,塑性增强。

The effects were investigated of different aging temperatures and holding time on the microstructure and mechanical properties of near beta type titanium alloy TLM.The results show that the characteristics of alloy microstructure after beta single phase solid solution and aging treatment are as follows：αphase precipitates out on both sides of the grain boundary along a certain crystal orientation in colony form,and there is also a large amount of precipitatedαphase inside the crystal grains.With the increase of aging temperature,the size of precipitatedαphase is gradually increasing and tends to be uniform,alloy strength is decreasing and ductility is increasing.When aging temperature rises from 480 ℃ to 510 ℃,the strengthening effect is the most obvious,and the increment of tensile strength reaches the maximum value of 184 MPa.When the temperature rises from 510 ℃ to 540 ℃,the increment of tensile strength reaches the minimum value equal to 63 MPa.With the increase of aging time,the size is obviously enlarged of precipitatedαphase along the grain boundary in colony form,there is also someαphase appearing in the precipitation-free zone,and its distribution gradually tends to be uniform.Aged at 480℃,alloy strength increases and ductility decreases with the increase of holding time.Aged at 510 ℃,alloy strength and ductility have no obvious change with the increase of holding time.Aged at 540 ℃,alloy strength is decreasing and ductility is increasing with the increase of holding time.