摘要
采用光电直读、金相观察、SEM、EDS、DSC和物相定量分析等方法,分析合金铸锭化学成分偏析程度,观察合金组织形态及不同均匀化热处理后合金铸锭结晶相的回溶,并定量分析残留相的面积分数。结果表明,Al-Zn-Mg-Cu合金大规格铸锭组织主要由树枝状α-Al相、枝晶间低熔点非平衡共晶相以及棒状析出相组成;合金铸态中主合金元素含量在铸锭厚度方向上T/4处最高。铸锭在470℃时保温48 h后组织中仍存在有较多的未溶S相(Al2CuMg相);在470℃均匀化保温24 h后,S相的面积分数变化不大。采用高温480℃/24 h均匀化热处理的均匀化效果好于470℃/48 h,合金铸锭中的S相面积分数由0.21%降低至0.04%。
The chemical composition segregation degree of alloy ingot was analyzed by means of photoelectric direct reading,metallo⁃graphic observation,SEM,EDS,DSC and phase quantitative analysis,and the microstructure morphology of alloy was observed.At the same time,the redissolution of crystallization phase of alloy ingot after different homogenization heat treatment was observed,and the area fraction of residual phase was quantitatively analyzed.The results show that the microstructure of Al-Zn-Mg-Cu alloy ingot is mainly composed of dendriticα-Al phase,interdendritic eutectic phase with low melting point and rod-like precipitates.The con⁃tent of main alloying elements in as-cast alloy reaches the maximum at T/4 along the direction of ingot thickness.There are still more undissolved S phase(Al2CuMg phase)in the ingot after holding for 48h at 470℃.After homogenizing and holding at 470℃for 24h,the area fraction of S phase changed little.The homogenization effect of high temperature 480℃/24h homogenization heat treat⁃ment is better than that of 470℃/48h homogenization,and the area fraction of S phase in alloy ingot decreases from 0.21%to 0.04%.
作者
杨璐
Yang Lu(Southwest Aluminum(Group)Co.,Ltd.,Chongqing 401326,China)
出处
《铝加工》
CAS
2022年第2期23-27,共5页
Aluminium Fabrication
