Fe含量对热挤压再生铝合金组织和性能的影响

采用光学显微镜、扫描电镜、万能拉伸机、显微硬度计等手段研究了不同Fe含量对热挤压再生铝合金组织和性能的影响,并探讨富Fe相形态演变机制。结果表明,Fe含量的增加有利于抑制再生铝晶粒尺寸的长大。随着Fe含量增加,晶粒尺寸逐渐减小,减小幅度达25%。热挤压后再生铝中富Fe相发生了折断和破碎,并沿着挤压方向呈带状分布。随着Fe含量增加,富Fe相的面积分数和平均长度均逐渐提高,当Fe含量分别为0.10%~1.24%时,面积分数和平均长度增长最快;而富Fe相的圆整度则随Fe含量的增加稍有降低。同时,再生铝的抗拉强度、屈服强度和伸长率均随着Fe含量的增加呈现逐渐降低的趋势,最大降低幅度分别为10.4%、23.2%和46.0%,而显微硬度则逐渐提高,最大提高幅度为21.7%。断口形貌也由纯韧性断裂转变为混合型断裂模式。

Effects of Fe Content on Microstructure and Properties of Hot Extrusion Recycled Aluminum Alloy

Effects of different Fe content on microstructure and properties of hot extrusion recycled aluminum alloy were investigated by optical microscopy,scanning electron microscopy,universal tensile machine and microhardness tester.Meanwhile,the evolution mechanism of iron-rich phase morphology was also described.The results show that the increase of Fe content is beneficial to suppress grain growth during extrusion and high temperature heat treatment process.Therefore the grain size is decreased gradually with Fe content increase,and the maximum decrease degree is reached to 25%.After hot extrusion,the iron-rich phase in the regenerated aluminum is broken and distributed in a strip shape along the extrusion direction.With the increase of Fe content,the area fraction and average length of iron-rich intermetallic phase are gradually increased,then area fraction and average length reach the maximum value when Fe content is 0.10%~1.24%,respectively,however,the roundness of the iron-rich phase is reduced slightly with the Fe content increase.Meanwhile,the tensile strength,yield strength and elongation of recycled aluminum present a decreasing trend with the increase of Fe,where maximum amplitude reach about 10.4%,23.2%and 46.0%,respectively,while the microhardness is increased gradually to21.7%.The fracture morphology is changed from a pure ductile fracture to a mixed fracture mode.