Static and Dynamic Thermo-Mechanical Behavior of Ti2AlC MAX Phase and Fiber Reinforced Ti2AlC Composites
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Ti 2 AlC MAX phase samples were processed by using Spark Plasma Sintering from commercially available Ti 2 AlC powder. Static and dynamic loading was performed by Universal Testing Machine and Split Hopkinson Pressure Bar (SHPB) respectively. The SHPB apparatus was modified to investigate the dynamic fracture initiation toughness. High speed photography was used to determine the fracture initiation time and the associated failure load. To widen applications, 20 vol% fiber of NextelTM-610 and NextelTM-720 have been added for the reinforcement of Ti 2 AlC, respectively. The results reveal that the peak compressive failure stress in dynamic conditions decreases with increasing temperatures, from 1,645 MPa at 25 C to 1,210 MPa at 1,200 C. The fracture experiments show that the dynamic fracture toughness is higher than the quasi-static value by approximately 35 %. The fracture toughness decreases with increase in temperature. The post mortem analysis of the fracture surfaces conducted using Scanning Electron Microscopy revealed that kinking along with intergranular cracking and delamination play important role in deformation of Ti 2 AlC. Compared to pure Ti 2 AlC, compressive fracture strength of 20 vol% Ti 2 AlC/720f and Ti 2 AlC/610f composites were enhanced by 39.7 and 32.6 % under static loading. The Society for Experimental Mechanics, Inc. 2015.