Effect of minor Cu content on microstructure and mechanical property of NiTiCu bulk alloys fabricated by crystallization of metallic glass powder

摘要: Abstract Ultrafine-grained Ni50.2−xTi49.8Cux (x = 0, 2.5, 5, and 7.5) bulk shape memory alloys were fabricated by sintering of metallic glass (MG) powder crystallization amorphous phase. Non-isothermal kinetic analysis reveals that the mechanism synthesized x = 5 MG is typical interface-controlled two dimensional growth nuclei followed volume diffusion-controlled three nuclei. In contrast, x = 7.5 in whole process. Correspondingly to different mechanisms, sintered crystallized (SCed) have same phases bcc B2, fcc NiTi2 phases, monoclinic B19′, but these display morphologies distributions. The SCed alloy has a microstructure B2 matrix surrounding phase region, while possesses discontinuous region. Consequently, mechanisms microstructures causes extreme high yield strength large plasticity for low no alloy. Especially, at least times counterpart prepared melt solidification. results provide method fabricating performance tailoring using metallurgy.