摘要
采用低温粉末冶金及热挤压工艺制备了具有超细晶组织的0.1%CNTs/AZ91 (质量分数)镁基复合材料。通过SEM、XRD、TEM对镁基复合材料的微观组织进行了表征,并对其室温力学性能进行测试。结果表明:CNTs在复合材料中分布均匀,CNTs的加入使得复合材料的晶粒尺寸从0.552μm细化到0.346μm,并促进了β相的析出,同时弱化了基面织构。复合材料的抗压强度和屈服强度分别达到了617和445 MPa,较基体提高了8.8%和7.2%;其抗拉强度和屈服强度分别达到了393和352 MPa,与基体相比分别提高了4.5%和6.0%。对强化机制进行分析,发现细晶强化和载荷传递是0.1%CNTs/AZ91复合材料的主要强化机制。
Magnesium alloys are well known for their low density, high specific strength. However,they are often limited by unsatisfactory mechanical properties. To meet the challenge of growing demand for light structural applications, metal matrix composites(MMCs) have attracted more attention. Carbon nanotubes(CNTs) have attracted much attention as the ideal reinforcements for MMCs due to their excellent mechanical strength and Young’s modulus. In this work, 0.1%CNTs/AZ91(mass fraction) magnesium matrix composites were prepared by low temperature powder metallurgy and hot extrusion. The magnesium alloy and composites were observed and analyzed by SEM, XRD and TEM. The room temperature mechanical properties of the composites were tested by Instron 5982 machine. The results showed thatthe CNTs distributed uniformly in the composites. The CNTs have an effect on reducing grain size, promoting precipitation of β-Mg17 Al12 and weakening basal texture. The compressive strength and yield strength of the composites reached 617 and 445 MPa, which increased by 8.8% and 7.2%, respectively.The tensile strength and yield strength were 393 and 352 MPa, which 4.5% and 6.0% MPa higher than the matrix, respectively. It can be found that fine grain strengthening and load transfer play a leading role in improving the strength in the 0.1%CNTs/AZ91 magnesium matrix composites.
作者
覃嘉宇
李小强
金培鹏
王金辉
朱云鹏
QIN Jiayu;LI Xiaoqiang;JIN Peipeng;WANG Jinhui;ZHU Yunpeng(Qinghai Provincial Key Laboratory of New L ight Alloys,Qinghai University,Xining 810016,China;Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and Forming,Qinghai University,Xining 810016,China;Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第12期1537-1543,共7页
Acta Metallurgica Sinica
基金
国家自然科学基金项目No.51661028
青海省重大科技专项项目No.2018-GX-A1~~
关键词
镁基复合材料
低温粉末冶金
显微组织
力学性能
强化机制
magnesium matrix composite
low temperature powder metallurgy
microstructure
mechanical property
strengthening mechanism
