Phys.org April 22, 2024
Refractory alloys are very resistant to heat and wear but are not ductile or resistant to fracture. A team of researchers in the US (UC Berkeley, Lawrence Berkeley National Laboratory, UC Irvine, Pacific Northwest National Laboratory) examined the strength and fracture toughness of the Single-phase body-centered cubic (bcc) refractory alloy, NbTaTiHf, from 77 to 1473 kelvin. Whereas the glide and intersection of screw and mixed dislocations promoted strain hardening controlling uniform deformation, the coordinated slip of <111> edge dislocations with {110} and {112} glide planes prolonged nonuniform strain through formation of kink bands. These bands suppressed strain hardening by reorienting microscale bands of the crystal along directions of higher resolved shear stress and continually nucleated to accommodate localized strain and distributed damage away from a crack tip… read more. TECHNICAL ARTICLEÂ
A map of the crystal structure of the alloy made with electron backscatter diffraction… Credit: Berkeley Lab