以5.2 mm厚度2195-T8铝锂合金为对象,进行重固溶、4.5%预变形后不同温度(145C~160℃)的T8再时效处理,研究其力学性能与晶内显微组织演化.结果表明:重固溶处理后的晶粒形态与原始2195-T8态晶粒形态一样,仍然保持为拉长的带状晶粒组织.重固溶并经4.5%预变形后,再采用适当的温度和时间进行T8时效处理,2195铝锂合金可以回复到原始T8态的显微组织和力学性能,即2195铝锂合金采用重固溶-T8再时效处理不会明显损害其力学性能.2195铝锂合金的晶内时效析出相包括T1相(Al2CuLi)、δ′相(Al3Li)、θ′相(Al2Cu)及θ″相(Al2Cu),其中优先析出相为T1相;较低温度及较短时间时效可形成较多δ′相和θ″相;随着时效时间延长,T1相生长,θ″相转化为θ′相并减少,δ′相消失;时效温度提高可促进该转变过程,加快铝锂合金的时效响应速度.
Based on 2195-T8 Al-Li alloy with 5.2 mm thickness, the mechanical properties and intragranular microstructural evolution during T8 (4.5% pre-deformation) re-aging at 145-160℃ after re-solution were investigated. The results show that the grain after re-solution still maintains as elongated pancake-like appearance, which is the same as that of original 2195-T8. The micro-structures and mechanical properties can recover to those of the original 2195-T8 Al-Li alloy through using appropriate T8 re-aging temperature and time. Re-solution and T8 re-aging treatment do not obviously damage 2195 Al-Li alloy mechanical property. The intragranular precipitates includeT1(Al2CuLi),δ′(Al3Li),θ′(Al2Cu) andθ″(Al2Cu), among which the preferential precipitates are T1 phases. Re-aging at lower temperature or for shorter time, much moreδ′ andθ″ precipitates are formed. With time extension,T1 precipitates grow, butθ″ precipitates are transformed toθ′ precipitates, andδ′ precipitates disappear. As re-aging temperature is elevated, the transformation process is accelerated, and the aging response is promoted.
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