Effect of hot isostatic pressing on microstructure and mechanical properties of Ti6Al4V-zirconia nanocomposites processed by laser-powder bed fusion
Amine Hattal, Kamilla Mukhtarova, Madjid Djemaï, Thierry Chauveau, Azziz Hocini, Jean Jacques Fouchet, Brigitte Bacroix, Jenõ Gubicza, G. Dirras
Abstract
This study discusses the effects of hot isostatic pressing (HIP) post-treatment on Laser Powder Bed Fusion of Ti6Al4V and Ti6Al4V reinforced with 1 wt% and 2.5 wt% of nano-yttria-stabilized zirconia (nYSZ). The bulk parts display a higher density after HIP post-treatment than the as-built counterparts. Besides, X-ray diffraction (XRD) analysis indicates a reduction of the β phase percentage after HIP. An increase in α grain thickness is noticed on both reinforced and unreinforced parts. Additionally, compared to their un-HIPed counterparts, the microhardness decreases after HIP post-treatment by 3%, 11%, 8% and 4% for the as-built Ti6Al4V, stress relieved Ti6Al4V, 1 wt% nYSZ reinforced and 2.5 wt% nYSZ reinforced parts, respectively. The same trend was observed for the yield stress, which decreases by 1%, 4% and 8%, for the as-built Ti6Al4V, stress relieved Ti6Al4V and 2.5 wt% nYSZ-reinforced parts respectively after HIP post-treatment, except for 1 wt% nYSZ-reinforced part, whose yield stress increase by about 7%, which could be attributed to the specific texture evolution within this material. The plastic strain was significantly enhanced after HIP in all materials.