车辆发动机缸体新型高强韧铝合金材料研究

发布时间：2018-02-28 16:42

  本文关键词： 铝硅合金 力学性能 组织 稀土元素　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：铸造铝硅合金具有比强度较高、质轻、耐腐蚀等良好的性能,被广泛的用于汽车、航空航天等领域,其中铝硅合金主要应用于制造发动机缸体、缸盖等铸件。随着汽车工业对产品轻量化和高强韧化的要求不断提高,提高铝硅合金的力学性能就成为迫切需要解决的问题。本文从材料的强韧化出发,以高纯铝为主加原材料,以AlSi7Cu2Mg铝合金(Si:6%-8%,Cu1.2%-1.8%,Mg0.2%-0.5%,Mn0.1%-0.2%)为基础,分别采用单项实验和正交试验的方法,优化合金元素的配比为(Si7%,Cu1.5%,Mg0.5%,Mn0.1%)。同时还对合金的熔炼工艺进行了研究,最终确定出细化剂Ti的加入量为0.15%,变质剂Sr元素加入量为0.06%时AlSi7Cu2Mg的细化和变质能够达到最佳效果。随后,本文系统地研究了不同热处理工艺对AlSi7Cu2Mg铝合金的力学性能和组织的影响,最终确定,最佳处理工艺为490℃×8h+540℃×8.5h+170℃×9.5 h,处理后合金的最高抗拉强度达到397 MPa,延伸率达到5.5%。本文还研究了不同含量的稀土元素Y和La对合金铸态组织与性能的影响结果表明:当Y含量为0.15%时,AlSi7Cu2Mg合金能够达到最好的力学性能,此时抗拉强度为238MPa,延伸率为4.5%,合金经T6热处理后在250℃的实验温度数值下抗拉强度达到了273MPa,延伸率为6.9%;含La的AlSi7Cu2Mg在La含量为0.3%时,铸态力学性能最好,抗拉强度为264MPa,经过热处理后合金的抗拉强度达到417MPa,此时的延伸率为5.9%。
[Abstract]:Cast Al-Si alloy has high specific strength, light weight, corrosion resistance and other good properties. It is widely used in automotive, aerospace and other fields, among which Al-Si alloy is mainly used in manufacturing engine cylinder block. Cylinder head and other castings. With the increasing demand of automobile industry for lightweight and high strength and toughness, improving the mechanical properties of Al-Si alloy has become an urgent problem to be solved. Based on high purity aluminum and AlSi7Cu2Mg aluminum alloy SiW 6-8 and Cu1.2and -1.8mg 0.2and -0.5m _ 0.2and -0.2um), the ratio of alloy elements is optimized by single experiment and orthogonal test, respectively. The melting process of the alloy is also studied. Finally, it is determined that the addition of Ti refiner is 0.15 and the addition of modifier Sr is 0.06. The refinement and modification of AlSi7Cu2Mg can achieve the best results when the addition amount of modifier Sr is 0.06. In this paper, the effects of different heat treatment processes on the mechanical properties and microstructure of AlSi7Cu2Mg aluminum alloy were systematically studied. The optimum treatment process is 490 鈩，

本文编号：1548119