摘要
采用金相显微镜、扫描电镜、透射电镜、常温拉伸、紧凑拉伸等实验手段研究固溶处理对7050铝合金拉伸力学性能和断裂韧性的影响。研究结果表明:单级固溶中,随着固溶温度的升高,粗大第二相逐渐溶解,但再结晶体积分数和亚晶尺寸逐渐增大,导致强度和断裂韧性均先增大后减小;双级固溶后,粗大第二相明显减少,再结晶体积分数和亚晶尺寸较小,强度和断裂韧性均超过单级固溶的最大值;固溶后预析出,虽然再结晶体积分数较低,亚晶尺寸较小,但亚晶界析出大量η相,基体内存在大量粗大第二相,强度和断裂韧性明显下降。
The influences of the solution heat treatment on the tensile properties and fracture toughness of the 7050 aluminum alloy were investigated by means of optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), the ambient temperature tensile tests and compact tension toughness testes. The results show that during the single-stage solution heat treatment, with the increase of solution temperature, coarse constituent particles are dissolved, and meanwhile, the percentage of recrystallization and the size of the subgrains increase. With the increase of solution temperature, the strength and fracture toughness firstly increase and then decrease. The two-stage solution heat treatment results in improved dissolution of coarse constituent particles, low recrystallization percentage and small size of subgrains. The strength and fracture toughness during the two-stage solution heat treatment are larger than the maximum of the single-stage solution heat treatment. The percentage of recrystallization and the size of the subgrains are small after pre-precipitation following solution heat treatment, but a large number of ηphase aggregates at the subgrain boundary. Meanwhile, constituent particles dissolve out again from the matrix, which leads to the decrease of the strength and fracture toughness.
出处
《中南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2012年第3期855-863,共9页
Journal of Central South University:Science and Technology
基金
国家重点基础研究发展规划('973'计划)项目(2005CB623700)
关键词
7050铝合金
固溶处理
强度
断裂韧性
aluminium alloy7050
solution heat treatment
strength
fracture toughness