中文摘要：

通过显微硬度和抗拉强度试验、X射线衍射仪、扫描电镜和金相显微镜观察，研究经旋转摩擦挤压法制备的CNTs／Mg复合材料的组织及性能。结果表明：CNTs／Mg复合材料的组织为细小等轴晶，且随着CNTs含量的增加，复合材料晶粒尺寸逐渐细化，当CNTs含量为5％时，晶粒尺寸最小，由63μm减小至3．79μm，为AZ91基材晶粒尺寸的6．01％。经过旋转摩擦挤压加工后基材内第二相13-Al12Mgl，相的量减少，CNTs的加入使复合材料中出现了Al4C3相，且第二相β-All：Mg17相网状结构消失。加工后的镁合金抗拉强度提高，最大值为330．9MPa，较原基材提高了90．6％，当CNTs含量小于2％时，复合材料强度高于原基材。复合材料硬度随着CNTs含量的增加呈先增加后降低的趋势，当CNTs含量为2％时，硬度最高，达101．3HV，比AZ91基材提高了40．3％。

英文摘要：

The microstructure and properties of carbon nanotubes reinforced magnesium （CNTs/Mg） composites fabricated by rotational friction extrusion were studied by the hardness and tensile strength test, X-ray diffraction, scanning electron microscopy and optical microscopy. The results show that the microstructure of CNTs/Mg composites is fine equiaxed grains, and with the in- crease of CNTs, the grain size gradually refined. When the content of CNTs is 5%, the composites obtain the minimum grain size which decreases from 63 μm to 3. 79 μm, accounting for 6.01% of AZ91 matrix. The second phase β-Al12 Mg17 phase of AZ91 matrix decreases after rotational friction extrusion processing, A14C3 comes up and the network structure of the second phase β-Al12 Mg17 phase disappear. The tensile strength of magnesium alloy increase after processing, the maximum value of 330. 9 MPa, compared with the original substrate increased by 90.6%, when the CNTs content of less than 2 %, the composite strength higher than the original substrate. The hardness of the composites first increases and then decrease. When the content of CNTs is 2 %, the hardness is 101.3HV, which is 40. 3% higher than AZ91 matrix.