Protium Absorption Properties of Ti-Cr-V Alloys in Low Hydrogen Pressure Regions

Ti–Cr–V alloys are known to absorb about 3.8 mass% of protium, but to desorb about 2 mass% because of the formation of stable protorides in low hydrogen pressure regions. However, few protium storage properties of the alloys in low hydrogen pressure regions were reported. This paper aims to clarify the protium absorption properties of Ti–Cr–V alloys in low hydrogen pressure regions. It was found that first low pressure plateau regions were coexistence regions of two different BCC phases for 20 at% V alloys. Decreasing V content and increasing Cr content turned out to shift the beginning of the second high pressure plateau regions to low protium concentration in unstabilizing the protorides in the first plateau regions. As a result, the Ti–52 at%Cr–20 at%V alloy was designed and found to have about 2.4 mass% protium desorption capacity in the width of the second plateau region at 273 K.