SiCp颗粒含量对SiCp/Mg-5Al-2Ca复合材料组织与性能的影响（英文）

Effects of SiCp Content on the Microstructure and Mechanical Properties of SiCp/Mg-5Al-2Ca Composites

通过搅拌铸造法制备了3种不同体积分数(2%,5%,10%)的SiCp/Mg-5Al-2Ca复合材料,并在673 K下进行了热挤压。铸态复合材料中,少量SiCp颗粒的加入就能破坏Al2Ca相沿基体合金晶界分布并有效细化Al_2Ca相析出尺寸。随着Si Cp体积分数的增高,Al_2Ca相尺寸有所减小,但不明显。经过热挤压后,Al2Ca相破碎并沿挤压方向排布,基体合金晶粒得到细化。晶粒尺寸以及Al2Ca相尺寸随着Si Cp体积分数的增高呈微小减小。与单组元基体合金相比较,挤压态Si Cp/Mg-5Al-2Ca复合材料的屈服强度和加工硬化率随着Si Cp体积分数的增高而逐渐增高,而延伸率则逐渐下降;抗拉强度最大值则出现在Si Cp体积分数为5%时。复合材料中Si Cp颗粒以及Al2Ca相的脱粘以及开裂是导致复合材料断裂的主要原因。

The Mg-5A1-2Ca alloys reinforced by 2vo1%, 5vo1% and 10vol% 5 μm SiCp were fabricated by stir casting. The cast composites were subject to hot extrusion. In the cast composites, addition of SiCp disturbs the network distribution of A1ECa phase along grain boundaries. After extrusion, grains of the matrix are refined further and the A12Ca phase break into particulates. Moreover, the Al2Ca phase and grain size can be further refined by the addition of SiCp. Compared with Mg-SA1-2Ca alloy, the addition of SiCp introduces obvious improvement of tensile yield strength （TYS） and work hardening rate, however, at the expense of elongation. Unlike the TYS, the ultimate tensile strength （UTS） of SiCp/Mg-SAl-2Ca composite does not change monotonously with increasing SiCp＇s content, and the highest UTS appears when the SiCp＇s volume fraction is 5%. The interfacial debonding between SiCp and Al2Ca phase and cracked particles are considered as the main crack source for SiCp/Mg-5Al-2Ca composite.