Investigation of Porosity Changes in Cast Ti6Al4V Rods After Hot Isostatic Pressing

The porosities of cast Ti6Al4V rods were investigated nondestructively using x-ray microcomputed tomography (microCT) before and after HIP. This allowed the visualization and quantification of porosity changes in the same samples, which indicate excellent pore closure for large pores. This is the first reported application of x-ray microCT for direct analysis of investment casting porosity before and after HIP. The method shows promise for further investigations using delayed HIP treatments or monitoring of pore closure at further varying HIP cycle settings. The nondestructive nature of the analysis has resulted in the interesting observation of small subsurface pores (< 250 mu m) unaffected by hot isostatic pressing in two of the samples.