Sensitivity of material failure to surface roughness: A study on titanium alloys Ti64 and Ti407

The relationship between material failure and surface roughness has been investigated using two titanium alloys: Ti64 the more ductile Ti407. Three types were created (polished, sandblasted scratched) with instances spanning a wide range of average roughness. surfaces tested in three-point bending imparted on tensile under-surface rectangular beam specimen. Results showed to be highly sensitive both magnitude orientation High maximum stress direction (and scratch like features perpendicular this direction) most detrimental. Thus, strain-to-failure work-to-failure) dropped off significantly increasing direction. Finite element modelling test indicated that cracks initiate at zones high plastic strain tips valleys due local curvature. can considered as series blunt crack-like where larger crack tip curvature induces greater likelihood propagation. Contrastingly, mechanical response Ti407 was insensitive owing its ductility. designers need aware sensitivity particular materials insensitivity is advantageous, but potentially serious if not properly accounted for.