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为解决颗粒增强铝基复合材料塑性加工困难的问题,采用脉冲电流辅助热拉深成形工艺。利用脉冲电流产生的焦耳热效应加热坯料,加热速度快、效率高,极大减少了坯料在加热过程中的热损耗。脉冲电流密度达到21.7A.mm-2时,坯料温度达到成形温度400℃。同时,铜电极和坯料之间安装的高电阻、低热传导率的不锈钢隔热片,有效地减小了坯料与电极间的热传导,提高了坯料的温度场分布均匀性。成形的工件表面质量光滑、形状精确、厚度均匀、无明显划伤和褶皱,圆角处无显微裂纹出现,尺寸精度达到±0.2mm。脉冲电流辅助热拉深成形工艺为SiCp/2024Al复合材料板材的塑性加工提供了一种高效、节能的绿色工艺方法。
In order to solve the problem of difficult plastic processing of particle reinforced aluminum matrix composites, the pulse current is used to assist the hot drawing process. The Joule heating effect generated by the pulse current heats the billet, which has high heating speed and high efficiency, and greatly reduces the heat loss of the billet during the heating process. Pulse current density reached 21.7A.mm-2, the blank temperature reached the forming temperature of 400 ℃. Meanwhile, the high resistance, low thermal conductivity stainless steel thermal insulation sheet installed between the copper electrode and the blank effectively reduces the heat conduction between the blank and the electrode, and improves the uniformity of the temperature field distribution of the blank. The surface quality of the formed workpiece is smooth, the shape is accurate, the thickness is uniform, there is no obvious scratches and wrinkles, no microcracks appear on the fillet, and the dimensional accuracy is up to ± 0.2mm. The pulsed current assisted hot drawing process provides an efficient and energy-saving green process for the plastic processing of SiCp / 2024Al composite sheet.