Role of face centered cubic/body centered cubic phase boundary crystallography on void growth

Abstract

In this work, using a mesoscale model, we investigate void growth as mediated by plastic slip at face-centered cubic (FCC)/body centered cubic (BCC) phase boundaries. We employ a large-strain elasto-visco-plastic fast Fourier transform (LS-EVP-FFT) crystal plasticity model with the advantage of treating smooth conformal void surfaces in a crystal. The calculations aim to identify the role of crystallographic orientation, phase boundary inclination, strain hardening, and BCC slip mode selection. To this end, both model FCC/BCC boundaries and FCC Cu/BCC Ta boundaries are considered, as well as commonly found phase boundary characters and a wide range of orientation relationships. We show that at Kurdjumov–Sachs (K–S) interfaces the void prefers to grow in the BCC crystal regardless of slip mode selection or hardening rate. The void grows faster when two slip modes $〈111〉\left\{110\right\}$ and $〈111〉\left\{112\right\}$ are available in the BCC grain than when only the $〈111〉\left\{110\right\}$ mode is available. The differing hardening rates expected of Cu and Ta lead to an overwhelmingly strong preference for void growth into the Ta side than the Cu side, regardless of orientations, orientation relationships, and phase boundary inclinations.