Development of Al356/SiCp cast composites by injection of SiCp containing composite powders
Development of Al356/SiCp cast composites by injection of SiCp containing composite powders
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DOI：
10.1016/j.matdes.2010.12.013
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发表时间：
2011-04-01
影响因子：
8.4
通讯作者：
Niroumand, Behzad
中科院分区：
文献类型：
--
作者：
Amirkhanlou, Sajjad;Niroumand, Behzad
生产铸造金属基复合材料的最大挑战之一是增强体的团聚倾向。这通常会导致颗粒分布差、孔隙率高和机械性能低。在目前的工作中，采用了一种新的方法，非常细的SiC颗粒的平均尺寸小于3 μ m的均匀分布。关键的想法是允许适当润湿的SiC颗粒在液态金属中逐渐原位释放。为此，将SiC颗粒以三种不同的形式注入熔体中，即，未处理的SiCp、研磨的颗粒状Al-SiCp复合粉末和研磨的颗粒状Al-SiCp-Mg复合粉末。然后将所得的复合浆料从全液体（搅拌铸造）或半固体（复合铸造）状态铸造。因此，铸造方法和注射粉末的类型对铸造复合材料的显微组织特征以及力学性能的影响进行了研究。结果表明，将球磨后的复合粉末代替未处理的SiC颗粒注入到熔体中，可显著改善SiC颗粒在基体中的分布，提高复合材料的孔隙率。从半固态而不是完全液态铸造具有类似的效果。通过注入研磨的复合粉末，掺入到基质中的SiC颗粒的平均尺寸也从约8 μ m显著减小到3 μ m。研究了Al 356/5vol. %合金的抗拉强度、屈服强度和延伸率由（Al-SiC（p）-Mg）（cp）注射熔体复合铸造制备的SiCp复合材料比由未处理的SiCp注射熔体搅拌铸造制备的复合材料分别提高了90%、103%和135%。(C)2010爱思唯尔有限公司版权所有。
One of the great challenges of producing cast metal matrix composites is the agglomeration tendency of the reinforcements. This would normally result in poor distribution of the particles, high porosity content, and low mechanical properties. In the present work, a new method for uniform distribution of very fine SiC particles with average size of less than 3 mu m was employed. The key idea was to allow for gradual in situ release of properly wetted SiC particles in the liquid metal. For this purpose, SiC particles were injected into the melt in three different forms, i.e., untreated SiCp, milled particulate Al-SiCp composite powder, and milled particulate Al-SiCp-Mg composite powder. The resultant composite slurries were then cast from either fully liquid (stir casting) or semisolid (compocasting) state. Consequently, the effects of the casting method and the type of the injected powder on the microstructural characteristics as well as the mechanical properties of the cast composites were investigated. The results showed that the distribution of SiC particles in the matrix and the porosity content of the composites were greatly improved by injecting milled composite powders instead of untreated-SiC particles into the melt. Casting from semisolid state instead of fully liquid state had similar effects. The average size of SIC particles incorporated into the matrix was also significantly reduced from about 8 to 3 mu m by injecting milled composite powders. The ultimate tensile strength, yield strength and elongation of AL356/5 vol.%SiCp composite manufactured by compocasting of the (Al-Sic(p)-Mg)(cp) injected melt were increased by 90%, 103% and 135%, respectively, compared to those of the composite manufactured by stir casting of the untreated-SiCp injected melt. (C) 2010 Elsevier Ltd. All rights reserved.