固溶温度对6082铝合金显微组织与性能的影响Effect of solution heat treatment temperature on microstructure and properties of 6082 aluminum alloy

研究固溶温度(480~580 ℃)对6082铝合金挤压板材的力学性能和晶间腐蚀性能的影响规律，结合金相显微镜、扫描电镜和扫描透射电镜对影响机理进行分析。结果表明：随着固溶温度的升高，合金的强度先升高后下降，在520~540 ℃时达到最高值；而伸长率呈现不断升高的趋势；晶间腐蚀的最大深度呈现先增加后降低的趋势。随着固溶温度的升高，残留结晶相的数量逐渐减少，时效后获得的β″沉淀强化相的尺寸更小、密度更高，晶界无沉淀析出区更窄，强度和伸长率更高；但温度过高时，再结晶严重，晶粒粗大，挤压效应消失，强度下降。固溶温度影响再结晶和亚晶粒大小以及晶界第二相析出状态和无沉淀析出带宽度，进而改变晶间腐蚀扩展路径及最大腐蚀深度。

The effect of solution heat treatment temperature on the mechanical properties and intergranular corrosion of the extruded sheets of 6082 aluminum alloy was investigated and the mechanism was discussed based on the microstructure examination by optical microscopy, scanning electron microscopy and scanning transmission electron microscopy. With the increase of temperature, the strength increases firstly to the maximum value at 520-540 ℃, then, decreases; while the elongation increases gradually; the maximum penetration depth of intergranular corrosion increases firstly, then, decreases. The increase of temperature tends to decrease the number of remnant phases and results in smaller β″ hardening precipitates with a higher density and consequently higher strength. However, too high temperatures result in coarse recrystallized grains, and thus, extrusion effect disappears and the strength decreases significantly. Solution heat treatment temperature has great effect on the recrystallization and size of subgrains, particles at grain boundaries and width of precipitates free zone adjacent to grain boundaries, therefore, changes the penetration path of IGC (Intergranular corrosion, IGC) and the maximum penetration depth.

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