热处理状态对限制模压-轧制2A97铝锂合金板材晶粒细化的影响

Effects of heat treatment state on grain refinement of constrained groove pressed-rolled 2A97 Al-Li alloy sheet

研究了热处理状态对2A97铝锂合金板材限制模压-轧制工艺晶粒细化和力学性能的影响。将2A97铝锂合金板材分别进行“固溶淬火(AQ)”及“固溶淬火+过时效(OA)”预处理,随后均进行限制模压-轧制试验。采用光学显微镜及电子背散射衍射进行金相观测,对板料进行硬度测试以评估其力学性能。结果表明,AQ态及OA态材料经过限制模压-轧制变形后晶粒均得到细化,同时材料硬度均得到提高;但由于OA态铝锂合金晶粒内有粗大析出相,经过限制模压后,晶粒内位错局部积聚阻碍整体晶粒细化,因此其晶粒细化及硬度提升效果弱于AQ态材料。

The effects of heat treatment state on grain refinement and mechanical properties of 2 A97 Al-Li alloy sheet by constrained groove pressing-rolling were investigated.The pretreatments of “as-quenched(AQ)” and “as-quenched+overaged(OA)” were carried out for 2 A97 Al-Li alloy sheet,and then constrained groove pressing-rolling tests were carried out.Optical microscope and electron back-scatter diffraction were used for metallographic observation and hardness tests were performed for sheet metal to evaluate mechanical properties.The results show that the grains of materials at AQ state and OA state are refined after constrained groove pressing-rolling and the hardness increases.However,due to the coarse precipitation phase in grains of Al-Li alloy at OA state,the accumulation of dislocations hinders the entire grain refinement after constrained groove pressing,therefore,the effect of grain refinement and hardness increase are lower than that at AQ state.