Martensitic transformation, mechanical and magnetic properties of Ni-Cu-Mn-Ti-(B) Heusler alloys by first-principles investigations

In order to explore the novel Ni-Mn-Ti-based all- d -metal Heusler alloy, the martensitic transformation, mechanical and magnetic properties of the Ni 2- x Cu x Mn 1.5 Ti 0.5 ( x = 0, 0.125, 0.25, 0.375, and 0.5) alloys and (Ni 2- x Cu x Mn 1.5 Ti 0.5 ) 0.97 B 0.03 ( x = 0, 0.125, 0.25, and 0.375) alloys were systematically investigated by the first-principles calculations. The austenite and non-modulated martensite always present an antiferromagnetic state in the investigated series. The phase stability of the austenite and martensite decreases with the increasing Cu content. Cu and B co-doping can decrease the thermal hysteresis of the Ni-Mn-Ti alloy. Doping B impedes the martensitic transformation of the Ni-Cu-Mn-Ti alloy and reduces the anisotropy of Ni-(Cu)-Mn-Ti alloy. The elastic constants of the Ni-Cu-Mn-Ti-(B) alloy were calculated, which reveals that the Ni-Cu-Mn-Ti alloy possesses great ductility and Ni-Cu-Mn-Ti-B alloy has great incompressibility, shear resistance, and normal stress resistance. The root of the martensitic transformation, mechanical and magnetic properties were discovered according to the electronic density of states.