触变注射成形法制备石墨烯纳米片增强镁基复合材料

Graphene Nanoplatelets Reinforced Magnesium Matrix Composites Fabricated by Thixomolding

采用触变注射成形的方法制备了石墨烯纳米片(GNPs)增强AZ91D镁基复合材料,利用OM、SEM、EDS、TEM和XRD研究了GNPs含量(0.3%、0.6%、0.9%,质量分数)对镁基复合材料微观组织的影响,并进行了力学性能测试。结果表明,GNPs在基体中呈条状均匀分布,与基体结合良好,GNPs的加入能够细化晶粒尺寸和减少孔隙。与AZ91D镁合金基体相比,GNPs的添加明显提高了复合材料的强度和硬度,当GNPs的含量为0.6%时,复合材料的力学性能最好,硬度和抗拉强度分别达到92.3 HV和245 MPa。

As a new type of carbon material reinforcement,graphene nanoplatelets(GNPs) have excellent mechanical,electrical,thermal and optical properties.Adding GNPs with a large specific surface area to the magnesium matrix can significantly improve the mechanical properties,the thermal and electrical properties of the magnesium matrix.However,so far,few reports focused on GNPs reinforced magnesium matrix composites,especially for lack of feasible fabrication technologies.Thus,in the present work,a new method for fabricating GNPs reinforced magnesium matrix composites is presented.First,the GNPs were dispersed by ultrasonic dispersion.Subsequently,the AZ91D magnesium alloy particles and the uniformly dispersed GNPs were mixed in a V-type powder mixer.Finally,GNPs reinforced magnesium matrix composites were prepared by semi-solid thixomolding.The effects of GNPs contents(0.3%,0.6%,0.9%,mass fraction) on the microstructure and properties of magnesium matrix composites were studied.The results show that the GNPs were uniformly distributed in the matrix,which were well combined with the matrix,and the addition of GNPs could refine the grain size and reduce porosity.Compared with AZ91D magnesium alloy,the addition of GNPs improved the tensile strength and hardness of the material.When the content of GNPs was 0.6%,the mechanical properties of the composites were the best,and the hardness and tensile strength reach up to 92.3 HV and 245 MPa.