Achieving ultra-high ductility and fracture toughness in molybdenum via Mo2TiC2 MXene addition

Abstract

Low ductility and toughness of molybdenum (Mo) alloys have usually been the bottleneck for their further application. Here, the improved strength together with ultra-high ductility and fracture toughness of Mo alloys were achieved by the incorporation of Mo2TiC2 (a typical MXene). Elongation of Mo–Mo2TiC2 alloys increased to 2.3–2.7 folds of pure Mo and the fracture toughness increased to 2.4 folds when Mo2TiC2 content rose to 2 wt%. Also, yield strength and tensile strength of Mo–Mo2TiC2 alloys increased slightly compared with pure Mo. The relationship between microstructural features and deformation behavior in Mo–Mo2TiC2 alloys was discussed to account for the toughening mechanisms, among which the high relative density, grain refinement, high low-angle grain boundaries (LGBs) proportion and strain hardening rate were the main reasons for the superior ductility (elongation, 39.4%–46.5%) in Mo–Mo2TiC2 alloys. Besides, the ultra-high toughness of Mo–Mo2TiC2 alloys was originated from not only the plastic deformation capacity, but also the crack deflection, particles pull-out and secondary cracking.