Void growth and coalescence in metals deformed at elevated temperature

For metals deformed at elevated temperatures the growth of voids to coalesc ence is studied numerically. The voids are assumed to be present from the b eginning of deformation, and the rate of deformation considered is so high that void growth is dominated by power law creep of the material, without a ny noticeable effect of surface diffusion. Axisymmetric unit cell model com putations are used to study void growth in a material containing a periodic array of voids, and the onset of the coalescence process is defined as the stage where plastic flow localizes in the ligaments between neighbouring v oids. The focus of the study is on various relatively high stress triaxiali ties. In order to represent the results in terms of a porous ductile materi al model a set of constitutive relations are used, which have been proposed for void growth in a material undergoing power law creep.