外力对高压模铸AA5754合金组织演变和力学性能的影响（英文）

发布时间：2018-09-14 14:11

【摘要】：在高压模铸AA5754合金前,分别采用超声处理和电磁搅拌或两者组合使用对熔体进行处理,并对其影响进行评定。经超声处理、电磁搅拌或组合处理后的合金熔体被转移至注射腔。对合金的晶粒尺寸、力学性能、含气量和热裂敏感性进行分析。结果表明,各种熔体处理方法都能使合金的晶粒细化,孔隙率减小。超声处理使合金晶粒从140μm减小至82μm,孔隙率从5.5%减小至1.4%。电磁搅拌使合金晶粒减小至107μm,孔隙率减小至3.3%。组合处理使合金晶粒和孔隙率降至该合金采用物理熔体处理方法有报道以来的最低值,分别为65μm和1.1%。强烈的空化效应和搅拌不仅可以得到细化的显微组织,而且也减小热裂敏感性,提高力学性能。以上特征都是由于在熔体处理过程中产生空洞。通过组合处理,电磁搅拌在强烈的超声空化场中提供更多外生颗粒以促进形核。超声处理通过引入强烈的空化场,在晶粒细化、减小热裂敏感性和含气量过程中起主要作用。
[Abstract]:The melt of AA5754 alloy was treated by ultrasonic treatment, electromagnetic stirring or both before high pressure die casting, and the effect was evaluated. The melt was transferred to the injection chamber after ultrasonic treatment, electromagnetic stirring or combination treatment. The grain size, mechanical properties, gas content and thermal cracking sensitivity of the alloy were analyzed. The results show that all kinds of melt treatment can refine the grain and reduce the porosity of the alloy. The ultrasonic treatment can reduce the grain size from 140 to 82 micron, and the porosity from 5.5% to 1.4%. Electromagnetic stirring can reduce the grain size to 107 micron and the porosity to 3.3%. The combined treatment can reduce the grain size and porosity of the alloy to 3.3%. Intense cavitation and stirring can not only refine the microstructure, but also reduce the thermal cracking sensitivity and improve the mechanical properties. All these characteristics are due to the formation of voids in the melt treatment process. Electromagnetic stirring (EMS) is strongly super-intense through combination treatment. More exogenous particles are provided in the acoustic cavitation field to facilitate nucleation. Ultrasonic treatment plays a major role in grain refinement, reducing cracking sensitivity and gas content by introducing a strong cavitation field.
【作者单位】： Department
【分类号】：TG292

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