Fracture and fatigue resistance of Mo–Si–B alloys for ultrahigh-temperature structural applications

Fracture and fatigue properties are examined for a series of Mo–Mo3Si–Mo5SiB2 alloys, which utilize a continuous α-Mo matrix to achieve unprecedented room-temperature fracture resistance (>20 MPa√m). Mechanistically, these properties are explained in terms of toughening by crack trapping and crack bridging by the more ductile α-Mo phase.