力学性能与断裂行为
( 1. 江苏大学 材料科学与工程学院, 镇江 212013;
2. 江苏大学 机械工程学院, 镇江 212013)
摘 要: 利用Al-Zr(CO3)2原位反应体系,采用熔体反应法制备了(Al3Zr+ Al2O3)p/Al复合材料。 XRD及SEM分析显示: 原位反应生成的颗粒为Al3Zr和Al2O3,颗粒细小并均匀分布在基体中。 拉伸实验表明: (Al3Zr+Al2O3)p/Al复合材料的抗拉强度和屈服强度随颗粒含量的增大显著提高,当颗粒体积分数为10%时, 复合材料的抗拉强度和屈服强度分别为148.3MPa和110.5MPa, 但延伸率先上升后下降。 原位拉伸研究表明:复合材料拉伸过程中裂纹的萌生及扩展机制可从两方面得到解释: 滑移过程中的位错作用机制以及颗粒脱粘和破碎形成的“孔洞”成核与长大机制。
关键字: 原位熔体反应法; 拉伸实验; 裂纹; 位错
( 1. School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China;
2. School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China)
Abstract: A new in-situ reactive system of Al-Zr(CO3)2 is used to prepare(Al3Zr+Al2O3)p/Al composites by melt method reaction. The XRD and SEM analysis indicate that the particles formed are fine Al3Zr and Al2O3, which are well distributed in the aluminum matrix. The ultimate tensile strength and yield strength are improved by increasing the volume fraction of the particle. The tensile properties are σb=148.3MPa and σs=110.5MPa when the particle volume fraction is 10%. But the elongation goes up firstly but then decreases. Crack initiation and propagation were observed by in-situ tensile experiment. The crack initiation and propagation can be interpreted with dislocation action mechanism and voids necleation and growth mechanism.
Key words: in-situ melt reaction method; tensile test; crack; dislocation