硼酸镁晶须增强镁基复合材料的室温及高温性能  

Mechanical Properties of the Mg_2B_2O_5w/AZ91D Composite at Room and Elevated Temperatures

作　　者：金培鹏[1] 王金辉[1] 丁雨田[2] 许广济[2] 马国俊[1] 刘孝根[3] 

机构地区：[1]青海大学镁技术工程研究所,青海西宁810016 [2]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050 [3]合肥通用机械研究院,安徽合肥230031

出　　处：《铸造技术》2010年第3期305-309,共5页Foundry Technology

基　　金：科技部国际合作项目;项目编号:2009DFA51830;青海省重大科技攻关项目;项目编号:2008-J-532

摘　　要：用真空气压渗流技术制备了Mg2B2O5w/AZ91D镁基复合材料,Mg2B2O5晶须在基体中均匀分布,材料无气孔缺陷,组织致密。硼酸镁晶须增强镁基复合材料具有细化的组织结构,弹性模量和抗拉强度相比镁合金有显著的提高、热膨胀系数明显降低。同时,对材料进行随着温度升高的力学性能测试,结果表明:复合材料的弹性模量、拉伸强度和规定非比例强度σ0.2随着温度的升高而降低,在超过225℃的服役条件下较室温条件下的强度和弹性模量大幅度下降,但塑性成形能力有所提高。Vacuum-gas pressure infiltration process was developed for fabricating the metal matrix composite reinforced by Mg2B2O5w. The whiskers were distributed uniformly in the matrix, and the dense mircrostructures with no porosity could be obtained in the as-cast Mg2B2O5w/AZ91D composite. The elastic modulus and tensile strength of the composites increased significantly compared to magnesium matrix alloy, while the thermal expansion coefficient reduced obviously. It indicates that the addition of Mg2 B255 whisker causes the strengthening behavior in AZ91D alloy and the stability of the composites is better than that of the matrix Mg alloy. The mechanical properties test results under elevated temperature show that elastic modulus and tensile strength of the composites and yield strength σ0.2 decrease with the temperature increasing. The elastic modulus and tensile strength dropped down obviously when working temperature over 225 ℃, compared with that at room temperature, but its ability of plastic deformation increases a little.

关 键 词：真空气压渗流 晶须预制块 镁基复合材料 微观组织 力学性能 

分 类 号：TB333[一般工业技术—材料科学与工程]