对低过热度浇注的半固态2024铝合金坯料分别以0.12, 0.26和0.52 ℃/s的平均升温 速率加热至625 ℃并保温; 利用光学显微镜和金相图像分析系统研究了升温速率对坯料部 分重熔组织的影响. 结果表明, 升温速率越快, 坯料重熔越快, 重熔后晶粒越细小和圆整. 提高升温速率, 有利于抑制晶间共晶相的溶解扩散和提高坯料的熔化过热温度, 加快晶间液 相形成, 对晶粒合并长大具有一定的抑制作用, 并加速晶粒球化.
The semi-solid 2024 alloy billets prepared by low superheat pouring were reheated to 625℃ with 7, 15.7 and 31.3℃/min, respectively, and then held isothermally. The effect of heating rate on the microstructure of billets was studied by optical microscope and metallographic image analysis system. The results show that with the prolongation of heating time, the liquid fraction increases gradually, the grains grow up quickly by the coalescence and then spheroidize gradually by the Ostwald ripening. The higher the heating rate is, the quicker the formation rate of liquid phase is and the finer and rounder the grains are. It is found through the analysis of microstructure evolution mechanism that accelerating the formation rate of liquid phase by increasing the heating rate can restrain the coalescence of grains to a certain extent, in which the growth rate of grains is decreased and the spheroidization rate is accelerated.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] | |
| [10] | |
| [11] | |
| [12] | |
| [13] |
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