Influences of Hydrogenation on Microstructure and Microhardness of Ti6Al4V Alloy
The microstructures of Ti6Al4V alloy after hydrogenation have been investigated and analysed by optical microscopy (OM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), and the influence of hydrogenation on the hardness of α and β phases has been analysed by microhardness testing. The microstructure observation revealed that δ hydride (fcc structure) precipitated in the specimens with 0.278 wt.% and 0.514 wt.% hydrogen, and a lot of dislocations and twins have been found simultaneously. The diffraction peaks moved to the lower angles because of the lattice expansion of β phase with the solution of hydrogen atoms. The result of microhardness testing shows that the hardness of α and β phases increases synchronously with increasing of hydrogen and the increment of β is larger than that of α. It is considered that the formation of δ hydrides, lattice defects and alloying element diffusion are the major factors leading to the microhardness change.
Young Won Chang, Nack J. Kim and Chong Soo Lee
J.W. Zhao et al., "Influences of Hydrogenation on Microstructure and Microhardness of Ti6Al4V Alloy", Materials Science Forum, Vols. 561-565, pp. 295-298, 2007