论文部分内容阅读
研究了不同熔体处理方法(普通电磁搅拌、化学细化法和环缝式电磁搅拌)对挤压铸造7075铝合金凝固组织及力学性能的影响规律。研究结果表明,环缝式电磁搅拌熔体处理技术显著减弱了普通电磁搅拌所固有的集肤效应对合金凝固组织的影响,增加了熔体所受的平均剪切速率,同时增加了单位体积熔体的散热面积,促使合金熔体的温度场和成分场更加均匀,有利于熔体“凝固初期晶核”瞬间大量生成,有利于获得细小均匀的凝固组织。对合金熔体同时进行环缝式电磁搅拌和添加Al-Ti-B化学细化剂处理,挤压铸造的7075铝合金显微组织变得更加细小、均匀、圆整,晶粒尺寸缩小为69μm,形状因子达到0.62。同时有效地提高了合金的力学性能。
The influence of different melt processing methods (ordinary electromagnetic stirring, chemical refining and ring gap electromagnetic stirring) on the solidification microstructure and mechanical properties of 7075 aluminum alloy by squeeze casting was studied. The results show that the annular seam electromagnetic stirring melt treatment technology significantly weakened the ordinary skin effect of electromagnetic stirring on the alloy solidification effect, increasing the average shear rate of the melt, while increasing the volume of unit melt Body cooling area, promote the alloy melt temperature field and component field more uniform, is conducive to the melt “early solidification nuclei ” a large number of instantaneous generation, is conducive to obtaining small and uniform solidified tissue. Simultaneously the ring-gap electromagnetic stirring and the addition of Al-Ti-B chemical refiner were carried out on the alloy melt. The die-cast 7075 aluminum alloy microstructure became finer, more uniform and rounded with the grain size reduced to 69μm , Shape factor of 0.62. At the same time effectively improve the mechanical properties of the alloy.