Mechanical Behaviors of the (Al3Zr+ZrB2)/A356 Composites Synthesized via In Situ Ultrasonic Chemistry Reactions

• 1、Jiangsu University, School of Materials Science and Engineering

Abstract：The particulates reinforcement (Al3Zr+ZrB2)/A356 composites are synthesized via ultrasonic chemistry melt in situ reactions, and the fracture behaviors are investigated with SEM in situ tensile observations and fracture surface characterizations. The results indicate that the tensile strength，yield strength and the elongation reach 403.61MPa, 343.98MPa and 8.9%, respectively. The crack initiation mechanisms are mainly dislocation actions mechanism during sliding, cavity formation mechanism due to the particle sloughing or bursting and the matrix defect induction mechanism. The crack growth is selective because of the non-uniform for the micro-distribution of the in situ particles. When the growing main cracks are faced to the particle-rich area, the growing direction is deflected to the particle-poor area, the cracks grow along the interface of the particle-rich area and the particle-poor area, and the macro-cracks are formed. The obvious dimple-crack characters on the SEM fracture surface of the composites are observed, and the fracture mechanism is plastic fracture.

Keywords： Composites Ultrasonic chemistry In situ tension Mechanical behavior