时效参数对Ti12LC钛合金组织及性能的影响

Effect of Aging Treatment on the Microstructure and Property of Ti12LC Titanium Alloy

本工作针对一种低成本Ti12LC钛合金的热处理,开展了固溶时效工艺实验,制定了不同热处理工艺方案,研究了不同时效温度及时效时间对钛合金微观组织和力学性能的影响。实验结果表明,时效温度对合金的组织和性能有较大的影响,在较低温度时,时效二次析出α相细小呈针状,随着温度升高,二次析出α相开始长大,在600℃时,变为尺寸粗大的片状α相,合金的强度降低,塑性升高。时效时间对合金的组织和性能也有较大的影响,时效时间较短时,析出的次生α相呈细针状,随着时间的延长,细针状的二次α相变为短片甚至球化,合金的强度先增大而后减小,其塑性则呈相反的趋势。Ti12LC钛合金的最佳强韧化条件为:(840±10)℃(空冷)+(560±5)℃×8h(空冷),在该热处理条件下,合金能获得较好的强度和塑性的匹配。

According to the heat treatment of a low-cost titanium alloy Ti12LC,this paper carried out solid solution aging process experiments,different heat treatment schemes were worked out,and the effects of aging temperature and time on the microstructure and mechanical properties of Ti12LC titanium alloy were studied.The results show that the aging temperature has a great influence on the structure and properties of the alloy.The secondary-precipitatedαphase is fine acicular at low temperature aging.With the increase of temperature,the secondary-precipitatedαphase begins to grow.At 600℃,the secondary-precipitatedαphase becomes massive flakyαphase.The strength of the alloy decreases and the plasticity increases.Aging time also has a great influence on the structure and properties of the alloy.The precipitated secondaryα-phase is fine acicular in a short time.With the increase of aging time,the secondaryα-phase becomes short sheet or even spheroidized.The strength of the alloy increases first and then decreases,while its plasticity has the opposite trend.The optimum heat treatment process of Ti12LC titanium alloy is(840±10)℃(air)+(560±5)℃×8h(air).With this heat treatment regime,the alloy can obtain better matching of strength and plasticity.