梯度功能复合材料,,.doc

采用铸造?倾析?铸造技术制备A390/A356铝合金 功能梯度复合材料时过热和凝固层厚度对其 界面接合的影响 Abstract: The cast?decant?cast is a new method for the preparation of the functionally graded components that has been developed in recent years. The functionally graded cylindrical shape component with a radial gradient, e.g. the first alloy (A390) with high wear resistance on the surface of the piece and toughness and the second alloy (A356) of low machining costs in the core of the piece can be produced via this melt process. The effectof the second alloy superheat at temperatures of 750, 820 and 860 °C as well as the effect of the first alloy solidified layer at 25, 35 and 45 s decanting time on achieving the perfect interface between the twoalloys was investigated. The characterization of the interface was carried out by optical microscopy and scanning electron microscopy,and its width was measured by the microhardness test. The results showed that the best interface was obtained at 860 °Cand 35 s decanting time with a width of 500 μm. Also, the wear resistance test was performed to measure and compare the surface wear resistance to the core. Key words: A390 alloy; A356 alloy; functionally graded material; cast?decant?cast process 摘 要：铸造?倾析?铸造技术是近年来发展起来的一种制备功能梯度材料的新方法。采用这种方法制备在径向具有梯度功能的圆柱形试样，其外表层为具有高耐磨性的A390铝合金，芯部为具有较高韧性和加工性能的A356铝合金。研究芯部熔体在不同过热温度(750，820和860 °C)和表层在不同倾析时间(25，35和45 s)下的A390/A356铝合金界面接合情况。采用光学显微镜和扫描电镜对界面进行表征，对界面区的显微硬度进行测量。结果表明，在 过热温度为860 °C，倾析时间为35 s的条件下，可以获得一宽度约为500 μm的接合良好的界面层。比较了试样表面层和芯部的耐磨性能。 关键词：A390铝合金；A356铝合金；功能梯度材料；铸造?倾析?铸造技术 1引言 工程中的许多组件需要材料特性，如，耐磨性和加工性，横截面的硬度和韧性。梯度功能材料（FGM）材料科学功能梯度材料沿厚度变化的材料[ 1 ]。在最近的几十年里，一些熔融工艺已被用于批量制作功能梯度材料。最常见的方法是离心铸造[ 2 ]，功率超声铸造[ 3 ]， 沉降[4]，磁分离[5]和熔体渗透[ ]。2005，都柏林大学开发生产功能梯度轻合金铸造新；该被称为铸造??铸造（CDC）。SCANLAN等人确定了三个与CDC进程相关联的技术：，内部和低压技术。通过这些方法的功能梯度材料，已被用于下面的模型。首先铝合金引入模具，让部分凝固在壁或核心，以形成一层。当层得到所需厚度，，然后引入模具。共同的步骤是倾析。这项工作的主要目的是制造一个在一个表面上径向具有高的耐磨性和硬度Al -Si合金FGM活塞另一个表面上或在一块的核心高切削性和韧性。生产Al Si合金FGM活塞的研究已经，如离心铸造然而，CDC（铸造?倾析?铸造）过程有能力生产径向梯度，这一过程，尤其是转换，已经有关其产品和其他功能梯度材料产品主