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采用热挤压法破碎铸态SiCp/AZ91镁基复合材料中的Mg_(17)Al_(12),对Mg_(17)Al_(12)破碎及弥散分布行为进行研究,并对复合材料的力学性能进行表征。结果表明:铸态SiCp/AZ91复合材料经热挤压后,不规则片状及线形Mg_(17)Al_(12)在基体合金和SiC颗粒的剪切应力场作用下,破碎成大量亚微米级的颗粒,并随基体合金的塑性变形发生重新分布,弥散分布在动态再结晶晶粒的晶界附近,通过钉扎晶界作用能够细化复合材料晶粒尺寸到2.3μm。此外,破碎化的Mg_(17)Al_(12)还起到弥散强化基体的作用,与晶粒细化协同作用,显著提高了复合材料的强度。
The crushing and dispersing behavior of Mg_ (17) Al_ (12) Mg_ (17) Al_ (12) in the as-cast SiCp / AZ91 magnesium matrix composites were investigated by hot extrusion. The mechanical properties of the composites Characterization. The results show that the as-cast sheets of SiCp / AZ91 composites are crushed into a large number of sub-micron grades under the action of shear stress of the matrix alloy and SiC particles after hot extrusion. Of the particles, and redistributed with the plastic deformation of the matrix alloy. The particles are distributed in the vicinity of the grain boundaries of the dynamically recrystallized grains. The grain size of the composite grains can be refined to 2.3 μm by pinning the grain boundaries. In addition, the fragmented Mg 17 Al 12 also played the role of dispersion strengthening matrix, and synergistic with the grain refinement, significantly enhanced the strength of the composites.