Effect of Hot Extrusion on Microstructures and Properties of TiB2/AZ31 Magnesium Based Composites

摘要:

采用原位合成-半固态搅拌铸造法制备了TiB2/AZ31镁基复合材料，研究了热挤压对TiB2/AZ31镁基复合材料组织和力学性能的影响。结果表明：热挤压不仅能显著细化合金组织，而且能有效改善TiB2颗粒分布的均匀性。与铸态AZ31镁合金相比，铸态TiB2/AZ31镁基复合材料的硬度、抗拉强度都有一定程度的提高。经过热挤压后，TiB2/AZ31镁基复合材料的硬度和抗拉强度分别比基体合金提高了126.2%和98.8%，达到950 MPa和322 MPa。磨损表面形貌显示，TiB2颗粒的引入以及对TiB2/AZ31镁基复合材料进行热挤压，都可有效地提高材料的耐磨性。

Abstract:

The TiB2/AZ31 magnesium based composite was fabricated by the in-situ synthesis-semisolid stirring technique, and its microstructure and mechanical property were studied. The results show that hot extrusion not only significantly refines the microstructure of the alloy, but also effectively improves the uniformity of TiB2 particles distribution. Compared with as-cast AZ31 magnesium alloy, the hardness and tensile strength of as-cast TiB2/AZ31 magnesium based composites increase to some extent (unobvious), but the elongation decreases. However, after extrusion, the hardness and the tensile strength of the as-extruded TiB2/AZ31 magnesium based composite increase by 126.2% and 98.8%, reaching 950 MPa and 322 MPa, respectively, and the elongation is also higher. Adding of TiB2 particles to AZ31 alloy and hot extrusion are effective ways to improve the wear resistance of AZ31 magnesium alloy.