Propagation mechanism of crack in adiabatic shear band of PM Ti-6Al-4V during hot deformation

Abstract

• The dominant crack is initiated in the interior of ASB. • The crack trend to join with the micro cracks and voids on prior-α/β trans interfaces. • Prior-α suppresses the crack propagation and plays an advantageous role. In this study, the propagation mechanism of crack based on microstructure has been investigated. Voids coalescence in adiabatic shear band is the initiation of dominant cracks. The deformation incompatibility between prior-α and β obtained from local strain accumulation and microstructure heterogeneity, leads to the formation of micro cracks and voids on prior-α/β trans interfaces. Micro cracks and voids on prior-α/β trans interfaces aggravate the crack propagation. Owing to the high hardness and stiffness of prior-α, crack has to consume more energy to penetrate or bypass prior-α. Therefore, the presence of prior-α can reduce the crack propagation rate, change the crack propagation direction and suppress the crack propagation.