【作者】 胡望杰；

【导师】 闫洪；

【作者基本信息】 南昌大学 ， 材料加工工程， 2011， 硕士

【摘要】 铝合金及其复合材料由于其优良的综合性能,广泛应用于汽车、航空航天等各个领域。其中,铝基复合材料是目前应用最为广泛的一种金属基复合材料,但由于受到制备工艺等诸多种因素的影响,铝基复合材料的强度、延伸率以及耐磨性等性能指标还不是十分理想,从而限制了其在一些领域上的应用。本文选用Y112铝合金作为基体材料,B4C颗粒作为外加增强相,采用机械搅拌法制备了半固态铝基复合材料,研究了不同的制备工艺和制备条件对半固态B4C/Y112铝基复合材料性能及组织的影响,并得出最佳的工艺参数。为进行性能比较,采用相同的工艺制备Y112铸态和半固态铝合金基体材料。对上述的制备的材料进行拉伸、硬度等力学性能测试,并采用扫描电镜观察拉伸断口,结果表明：半固态铝基复合材料的硬度随着加入B4C颗粒的质量分数增加而不断增大,12wt%-B4C/Y112复合材料硬度值最高,达到136HV;其抗拉强度,随着B4C含量的增加呈先上升后下降趋势；半固态复合材料的延伸率要高于铸态基体的延伸率,但总体来说,延伸率都偏低。半固态铝基复合材料的断口随着加入B4C颗粒的质量分数不同而呈现不同的形貌,多为脆性断裂。采用M-2000型磨损实验机对半固态基体和半固态复合材料进行干摩擦滑动磨损实验,分析了在相同滑动摩擦速度,不同B4C含量的复合材料的磨损性能,并探讨了复合材料的磨损机理,结果表明：材料的磨损都是若干种磨损机理的综合作用的结果；随着载荷的增加,材料的磨损率逐渐升高；在相同的摩擦条件下,半固态复合材料的磨损性能要优于半固态基体,且其抗磨损的能力随着加入B4C颗粒的质量分数增加而更趋明显。更多还原

【Abstract】 Aluminum alloy and its Composites widely used in automotive, aerospace and other fields because of its excellent properties. Among them, aluminum matrix composite material is one of the most widely used of metal matrix composite materials,but due to the preparation technology, and many other kinds of factors, its strength,elongation and wear resistance performances is not quite ideal, thus limiting its application in some areas. In this research we chose Y112 alloy as the matrix and boron carbide (B4C) as the plus reinforcement, prepared semi-solid aluminum matrix composites by mechanical mixing method. We studied the microscopic structure and mechanical property of semi-solid B4C/Y112 aluminum matrix composites affected by different preparation process and condition,and found the optimum process technology. In the same way, Y112 cast alloys and Y112 semi-solid alloys were also prepared for the purpose of performance comparison investigation.Tested the tensile, hardness and other mechanical properties of materials, and observed tensile fracture by scanning electron microscopy. The results showed that: the hardness of semi-solid aluminum matrix composites increase with the concentration of B4C particles’rasied,12wt%-B4C/Y112 composite have the highest hardness, reached 136HV. With the B4C particles contents increaseing, its tensile strength first increased and then decreased. Semi-solid composites’elongation is higher than the elongation of the cast matrix, but overall, the elongation are low. The fracture surface of semi-solid matrix composites show different morphology because of different concentration of B4C particles, mostly are brittle fracture.Dry sliding wear behaviour of semi-solid matrix and semi-solid composites were investigated by M-2000 type wear test machine, analyzing the wear abilities of composite material which contains different concentration of B4C particles, exploring the wear mechanism of the composites. The results showed that:the abrasion of the materials is the result of several kinds of wear mechanism that have comprehensive impaction; with the increase of load, The material wear rate raised gradually. Under the same condition of friction, the wear abilities of semi-solid composite material is better than semi-solid matrix, even the ability of anti-wear-out is increased by the raising percentiges with adding the B4C paticles.更多还原