In-situ SEM characterization of fracture mechanism of TiB/Ti-2Al-6Sn titanium matrix composites after electroshocking treatment

In this article, in-situ scanning electron microscope characterization of the tensile properties of TiB/Ti-2Al-6Sn titanium matrix composite (TMC) was conducted before and after electroshocking treatment (EST). After EST, the tensile strength increased by 113.2 MPa. The effect of EST on the tensile strength and fracture behavior of TiB was investigated using in-situ characterization of the fracture morphology and crack propagation path of the matrix and TiB. Before EST, TiB fracture introduced cracks that extended into the matrix, resulting in material failure. After EST, the refined TiB improved the bearing capacity of the matrix, thereby improving TMC strength. Moreover, after EST, the cracks were introduced into the matrix, and resulting the fracture of matrix first. With an increase in the external load, cracks in the matrix were observed to propagate to TiB, and the refined TiB was fractured, detached, and pulled out, resulting in the formation of pores. Analyzing the propagation path of the main crack after EST showed that the deflection angle of the main crack increased. The microstructure of the fracture surface indicated that the fracture of the matrix was plastic, whereas that of TiB was brittle. After EST, the size and area of the dimples increased, confirming the increase in plasticity. The results revealed that the comprehensive mechanical properties of TiB/Ti-2Al-6Sn improved after EST. Hence, EST is an efficient method for tailoring the microstructures and mechanical properties of TMCs.