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在20~220℃范围内对比研究了AZ80、AZ31、ZK60镁合金和AA6082铝合金在大气中的散热性能,分别测量其环境散热曲线并用指数型热动力学方程T=T_0+ΔT_0·exp(-t/A_0)拟合。结果表明,固溶处理可使铸态或挤压态镁合金热导率下降,而固溶+时效处理后其热导率有所提升。分析了瞬时温差与瞬时温度比值ΔT/T与镁合金、铝合金散热性能的关系,自然对流条件下,柱高对AZ80镁合金散热性能影响较小;在人工强制对流条件下,当0.25<ΔT/T<0.45时,高柱(60 mm)散热速率约为低柱(20 mm)的两倍。在自然对流条件下,AZ80、AZ31镁合金的散热性能在0.25<ΔT/T<0.45(120~220℃)时,明显优于AA6082铝合金。在0.05<ΔT/T<0.25(20~120℃)时,这3种合金的散热性能无明显差别。
The heat dissipation performance of AZ80, AZ31 and ZK60 magnesium alloys and AA6082 aluminum alloy in the atmosphere were compared in the range of 20 ~ 220 ℃. The exothermic curves were measured and the exponential thermodynamic equations T = T_0 + ΔT_0 · exp (- t / A_0). The results show that the solution heat treatment can reduce the thermal conductivity of as-cast or extruded magnesium alloys, while the thermal conductivity of the solution increases after solution treatment and aging treatment. The relationship between instantaneous temperature difference and instantaneous temperature ratio ΔT / T and the heat dissipation performance of magnesium alloy and aluminum alloy was analyzed. Under the condition of natural convection, column height had little effect on the heat dissipation performance of AZ80 magnesium alloy. Under the condition of artificial convection, when 0.25 <ΔT /T<0.45, the high column (60 mm) heats up approximately twice as fast as a low column (20 mm). Under the condition of natural convection, the heat dissipation performance of AZ80 and AZ31 magnesium alloy is better than that of AA6082 aluminum alloy when 0.25 <ΔT / T <0.45 (120 ~ 220 ℃). At 0.05 <ΔT / T <0.25 (20 to 120 ° C), there is no significant difference in heat dissipation between the three alloys.