CAJ | 학술논문

研究了单一和复合Al-5Ti-B、RE和Al-10Sr细化变质剂对砂型铸造Al-7.5Si-4Cu合金力学性能、显微组织、细化变质效果及其金属间化合物变化的影响。结果表明：与单一细化变质处理以及铸态相比，经过添加质量分数为0.8%的 Al-5Ti-B、0.1%的 RE 和0.1%的 Al-10Sr 细化变质剂复合细化变质处理后铸造 Al-7.5Si-4Cu合金的力学性能和显微组织都得到了显著改善。对于单一细化变质处理，加入0.8%的Al-5Ti-B中间合金后，合金的抗拉强度和布氏硬度得到大幅度提高，并且细化了α(Al)相。加入0.1%的RE中间合金后，合金的伸长率得到了最大程度的提高。这是因为RE的加入使铝合金熔液而得到净化，同时改变了金属间化合物的形状。而加入0.1%的Al-10Sr变质剂后，合金的屈服强度得到改善，但其他性能的改善有限。Al-10Sr变质剂对共晶硅具有较强的变质作用，但使得铝合金熔体含气量增加并形成严重的柱状晶组织。利用硅相的平均面积和长宽比描述细化变质效果得到的结论与力学性能和组织分析的结果相同。
연구료단일화복합Al-5Ti-B、RE화Al-10Sr세화변질제대사형주조Al-7.5Si-4Cu합금역학성능、현미조직、세화변질효과급기금속간화합물변화적영향。결과표명：여단일세화변질처리이급주태상비，경과첨가질량분수위0.8%적 Al-5Ti-B、0.1%적 RE 화0.1%적 Al-10Sr 세화변질제복합세화변질처리후주조 Al-7.5Si-4Cu합금적역학성능화현미조직도득도료현저개선。대우단일세화변질처리，가입0.8%적Al-5Ti-B중간합금후，합금적항랍강도화포씨경도득도대폭도제고，병차세화료α(Al)상。가입0.1%적RE중간합금후，합금적신장솔득도료최대정도적제고。저시인위RE적가입사려합금용액이득도정화，동시개변료금속간화합물적형상。이가입0.1%적Al-10Sr변질제후，합금적굴복강도득도개선，단기타성능적개선유한。Al-10Sr변질제대공정규구유교강적변질작용，단사득려합금용체함기량증가병형성엄중적주상정조직。이용규상적평균면적화장관비묘술세화변질효과득도적결론여역학성능화조직분석적결과상동。
Al-7.5Si-4Cu cast alloy melt modified by Al-5Ti-B, RE and Al-10Sr master alloys were poured in the chromite sand moulds, to investigate comparatively the effects of individual or combined additions of grain refiners and modifiers on the mechanical properties, microstructures, grain refining and modification, and intermetallic compounds of the alloy. The results show that the mechanical properties and the microstructures of Al-7.5Si-4Cu cast alloys are improved immensely by combining addition of 0.8%Al-5Ti-B, 0.1%RE and 0.1%Al-10Sr grain refiners and modifiers compared with the individual addition and cast conditions. For individual addition condition, addition of 0.8%Al-5Ti-B master alloy can obtain superior tensile strength, Brinell hardness and finer equiaxedα(Al) dendrites. The alloy with 0.1%RE master alloy shows the highest improvement in ductility because the rare earth can purify the molten metal and change the shape of intermetallic compounds. While the alloy with 0.1%Al-10Sr modifier shows only good improvement in yield strength, and the improvement of other performance is unsatisfactory. The Al-10Sr modifier has a significant metamorphism for the eutectic silicon, but will make the gas content in the aluminum alloy melt increase to form serious columnar grain structures. The effects of grain refining and modification on mean area and aspect ratio have the same conclusions obtained in the mechanical properties and the microstructures analyses.