6070铝合金的均匀化热处理

通过OM、SEM、EDS、DSC和电导率等测试方法，研究了6070合金的均匀化热处理工艺及微观组织演变。结果表明，6070合金铸态组织中，大量非平衡凝固产生的一次相Mg₂Si沿晶界聚集分布，圆盘状Q相分布于晶内。合金经535℃×12 h均匀化处理后，铸态一次相基本回溶，均匀化效果较好。均匀化后合金元素主要以细小弥散相形式在铝基体中析出，导致合金导电率升高。550℃为合金起始过烧温度，合金组织中开始出现近似三角形的复熔相和晶界复熔变宽的过烧特征，随着均匀化温度的升高和时间延长，合金过烧加重，导电率下降，晶粒和含Mn弥散相尺寸变大，同时形成粗大过烧相Q相。

Homogenization heat treatment of 6070 aluminum alloy

Homogenization heat treatment process and microstructure evolution of 6070 alloy were studied by means of OM, SEM, EDS, DSC and conductivity measurements. The results show that in the as-cast 6070 alloy, a large amount of Mg₂Si primary phases produced by non-equilibrium solidification are aggregated and distributed along the grain boundary, and disc-shaped Q phase is distributed in the grains. After 535 ℃×12 h homogenization heat treatment, the primary phase in the as-cast alloy is basically redissolved, and the homogenization effect is good. After homogenization, the alloying elements are mainly precipitated in the aluminum matrix in the form of fine dispersed phase, leading to the increase of conductivity. The overburning starting temperature of the alloy is 550 ℃, at which the overburned characteristics including nearly-triangular remelting phase and grain boundary widening by remelting begin to appear in the alloy. With the increase of homogenization temperature and extension of time, the overburning of the alloy increases and the conductivity decreases, the grain size and Mn containing dispersed phase size become larger, and the coarse overburned phase Q is formed concurrently.