摘要
采用高能球磨结合粉末冶金工艺制备了碳纳米管(CNT)含量(体积分数)分别为0、1%和3%的CNT/7055Al复合材料。采用OM、SEM、TEM以及拉伸实验等方法研究了CNT/7055Al复合材料的CNT分布、晶粒结构、近界面结构及力学性能,分析了复合材料的强化机制和各向异性。结果表明,CNT/7055Al复合材料为无CNT的粗晶区与富集CNT的超细晶区组成的双模态晶粒结构;CNT在Al基体的超细晶区中分散良好,CNT-Al界面干净清洁,界面反应产物少;3%CNT/7055Al复合材料沿挤压方向的抗拉强度达到816 MPa,但延伸率仅为0.5%。细晶强化和Orowan强化是CNT/7055Al复合材料主要的强化机制。由于CNT沿不同方向的增强效率不同以及粗晶条带组织的存在,复合材料表现出比基体合金更强烈的各向异性,在垂直挤压方向的拉伸性能要弱于沿挤压方向的拉伸性能。
In the recent years,lightweight and high-strength structural materials have gained much attention in engineering applications.Carbon nanotube(CNT)-reinforced Al(CNT/Al)composites are promising structural materials owing to the good mechanical properties and high reinforcing efficiency of CNTs.Previous studies on these composites mainly focused on fabricating CNT-reinforced low-strength or medium-high-strength Al alloys(such as pure Al,or 2xxx series or 6xxx series Al alloys)composites via various dispersion methods.However,only few studies investigated composites with super-high-strength Al alloys as the matrices.In the present work,CNT/7055Al composites with CNT volume fractions of 0%,1%,and 3%were prepared by high-energy ball milling combined with powder metallurgy.The CNT distribution,grain structure,interface,and mechanical properties of the CNT/7055Al composite were investigated using OM,SEM,TEM,and tensile tests.The strengthening mechanism and anisotropy of the composite were analyzed.The results indicated that the composite had a bimodal grain structure consisting of CNT-free coarse grain zones and CNT-enriched ultrafine grain zones.CNTs were well dispersed in the ultrafine grain zones of the Al matrix,and the CNT/Al interface was clean.There were only few reaction products at the interface.The tensile strength of the 3%CNT/7055Al composite reached 816 MPa,but the elongation was only 0.5%.Grain refinement and Orowan strengthening were the main strengthening mechanisms of the CNT/7055Al composite.Because of the load transfer efficiency of CNTs and a coarse grain band structure,the composite exhibited stronger anisotropy than the matrix alloy.The tensile properties of the CNT/7055Al composite normal to the extrusion direction were weaker than those in the extrusion direction.
作者
毕胜
李泽琛
孙海霞
宋保永
刘振宇
肖伯律
马宗义
BI Sheng;LI Zechen;SUN Haixia;SONG Baoyong;LIU Zhenyu;XIAO Bolv;MA Zongyi(Shi-Changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China;Beijing Institute of Aerospace Systems Engineering,Beijing 100076,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第1期71-81,共11页
Acta Metallurgica Sinica
基金
国家自然科学基金项目Nos.51931009、51871214和51871215
国家重点研发计划项目No.2017YFB0703104
中国科学院前沿科学重点研究计划项目No.QYZDJ-SSW-JSC015
中国科学院青年创新促进会项目No.2020197
关键词
碳纳米管
铝基复合材料
力学性能
各向异性
高能球磨
粉末冶金
carbon nanotube(CNT)
aluminum matrix composites
mechanical property
anisotropy
high-energy ball milling
powder metallurgy
