Effects of dehydrogenation heat-treatment on electrical–mechanical properties for hydrogenated Cu–3 mass%Ti alloys

In our previous study, we reported that remarkable simultaneous improvements of mechanical strength and electrical conductivity are achieved in the hydrogenated Cu–3 mass%Ti alloy. The hydrogen heat-treatment at 350 °C under hydrogen pressure of 7.5 MPa for 48 h proceeds with the decomposition to Cu-rich phase and Ti-hydride. The present investigation focused on dehydrogenation heat-treatment for the hydrogenated Cu–Ti alloys. Two kinds of hydrogen desorption peaks of the hydrogenated Cu–3 mass%Ti alloy at 250 °C and 550 °C were observed in the TDS measurement. The lower peak would be caused by desorption of hydrogen trapped by the defects such as dislocations. The higher temperature peak would be corresponded to the decomposition Ti hydride. In consequence, the tensile strength of the hydrogenated alloy decreased with increasing dehydrogenation temperature more than 400 °C. The plastic deformations of the alloys with dehydrogenation at more than 350 °C were observed in the S–S curves, and then the yield strains of the alloys drastically increased. High tensile stress and ductility were simultaneously obtained by optimum dehydrogenation treatment at 350–375 °C.

► The hydrogenated Cu–3 mass%Ti alloy had two kinds of thermal hydrogen desorption. ► The ductility of the alloy increased after dehydrogenation at more than 350 °C. ► The dehydrogenation at 350–375 °C of the alloy lead to obtain high tensile stress.