论文部分内容阅读
采用OM、SEM及硬度测试等手段研究了均匀化退火处理对Al-4.8Zn-1.6Mg合金微观组织与性能的影响。结果表明:合金铸态组织主要由α-Al和晶界处非平衡低熔点第二相组成。随着退火温度升高或保温时间延长,晶界上熔点较低的非平衡第二相逐渐回溶到α-Al中,偏析现象基本消除,合金元素分布趋于均匀。在退火时间保持不变时,随着退火温度升高,合金硬度逐渐上升。当退火温度不低于315℃时,随退火时间的延长,合金硬度呈下降趋势。当退火温度超过355℃时,随着退火时间的延长,合金硬度逐渐上升。该合金适宜的均匀化退火处理工艺为465℃/24 h。
The effects of homogenization annealing on the microstructure and properties of Al-4.8Zn-1.6Mg alloy were investigated by OM, SEM and hardness test. The results show that the as-cast microstructure of the alloy consists mainly of α-Al and the second phase of non-equilibrium low melting point at the grain boundary. With the increase of annealing temperature or holding time, the non-equilibrium second phase with lower melting point in the grain boundary gradually returns to α-Al, the segregation phenomenon is basically eliminated, and the alloying element distribution tends to be uniform. When the annealing time remains the same, as the annealing temperature increases, the hardness of the alloy gradually increases. When the annealing temperature is not lower than 315 ℃, the hardness of alloy decreases with annealing time. When the annealing temperature exceeds 355 ℃, with the annealing time, the alloy hardness gradually increased. The suitable homogenization annealing process for this alloy is 465 ℃ / 24 h.