Mechanical and corrosion properties of lightweight (Ti60Cr30Nb10)100-xAlx medium-entropy alloys

Microstructure, mechanical properties and corrosion behavior of lightweight (Ti60Cr30Nb10)(100-x)Al-x (x=0, 5, 7.5 and 10, at.%) medium-entropy alloys (MEAs) were investigated in the as-cast and homogenized states. As the Al content increases from 0 to 10 at.%, all the as-cast MEAs consist of identical phase composition, i.e., a body-centered cubic (BCC) phase and a small amount of TiCr2 Laves phase. After the homogenization, all the homogenized MEAs show a single BCC phase. The (Ti60Cr30Nb10)(95)Al-5 MEA shows the most excellent mechanical properties both in as-cast and homogenized states among the studied alloys, displaying yield strengths of similar to 1048 MPa and similar to 1017 MPa along with the compression strain exceeding 50%. Additionally, compared with the TC4 and the as-cast (Ti60Cr30Nb10)(95)Al-5 alloys, the homogenized (Ti60Cr30Nb10)(95)Al-5 alloy shows superior corrosion resistance due to its uniform microstructure and chemical composition.