【作者】 孙常明；

【导师】 史志铭；

【作者基本信息】 内蒙古工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 本论文采用富Ce混合稀土和Mn变质的方法,改善铝合金中富铁相的形貌来提高铝合金的力学性能,并考察了Fe含量、冷却速度及变质剂含量对富铁相及铝合金组织和力学性能的影响。研究结果表明:在工业纯铝中,冷速越大,富铁相形貌越细小。当含Fe量小于1wt%时,富铁相呈细小的颗粒状,反之,富铁相呈短棒状、长针状分布。在含Fe量为1wt%～2wt%的工业纯铝中,添加0.5wt%稀土时,富铁相呈细小的颗粒状。在含Fe为0.5wt%的工业纯铝中添加0.3wt%RE时,抗拉强度为117.4MPa,延伸率为50.6%,对比未变质时,分别提高了38.6%和15.5%。在含Fe为0.12wt%的Al-7Si-0.3Mg合金中添加0.1wt%RE进行变质处理时,富铁相和共晶Si相呈细小的颗粒状。此时,合金抗拉强度为166MPa,延伸率为5.5%,对比未变质时,分别提高了10%和94.3%。在含Fe为0.2wt%的Al-7Si-0.3Mg合金中添加0.2wt%RE进行变质处理时,富铁相和共晶Si相呈细小的颗粒状。此时,合金抗拉强度为169MPa,延伸率为5.28%,对比未变质时,分别提高了14.2%和252%。在Al-7Si-0.3Mg-0.15RE合金中,Fe含量增至0.3wt%时,大部分富铁相呈针状。在含Fe为0.5wt%的Al-7Si-0.3Mg-0.15RE合金中加入Mn元素改善富铁相形貌效果显著。当Mn/Fe比值为1.4时,富铁相尺寸最细小,此时,合金的延伸率为13.1%,对比未变质时提高了363%。当Mn/Fe比值为2时,富铁相已经完全的破碎。此时,合金的抗拉强度为180MPa,对比未变质时提高了7.1%。更多还原

【Abstract】 This paper aims to improve the morphology of Fe-riched phase in aluminum alloys by using the modification of Ce-riched rare-earth mixture and Mn. The effect of Fe content、cooling rate and modification content on Fe-riched phase, microstructure and mechanical properties of aluminum alloys were investigated.The investigative results show that, with cooling rate increasing, the morphology of Fe-riched phases decrease in commercial pure aluminum. When Fe content less than 1wt%, Fe-riched phase are fine particle, In contrary, Fe-riched phase are distributed in the form of short rodlike or long needlelike, when adding 0.5wt%RE in commercial pure aluminum with 1wt%～2wt%Fe , Fe-riched phase are fine particle. In commercial pure aluminum with 0.5wt%Fe, adding 0.3wt%RE obtains a tensile strength and an elongation of 117.4MPa and 50.6%respectively, enhancing by 38.6% and 15.5% than the unmodification.In Al-7Si-0.3Mg alloys with 0.12wt%Fe, adding 0.1wt%RE makes the Fe-riched phase and eutectic Si phase to be fine particles. Besides, the tensile strength and elongation can respectively achieve at 166MPa and 5.5%, by contrast with unmodification respectively enhanced by 10% and 94.3%. In Al-7Si-0.3Mg alloys with 0.2wt%Fe, adding 0.2wt%RE leads the Fe-riched phase and eutectic Si phase to be fine particles; the tensile strength and elongation can respectively achieve at 169MPa and 5.28%, enhancing by 14.2% and 21.9% than the unmodification respectively.In Al-7Si-0.3Mg-0.15RE alloys, when the Fe content achieves at 0.3wt%, Fe-riched phase are mostly needlelike. Mn modification to Al-7Si-0.3Mg-0.15RE alloys with 0.5wt%Fe greatly affects the morphology of Fe-riched phases. When the ratio of Mn/Fe is 1.4, the size of Fe-riched phase is the smallest; the elongation of the alloys can achieve at 13.1%, enhancing by 363% than the unmodification. When the ratio of Mn/Fe is 2, the Fe-riched phases are broken up; the tensile strength of the alloys can achieve at 180MPa, enhancing by 7.1% than unmodification.更多还原