Preparation and properties of Fe-Mn-Si-Cr-Ni shape memory alloy

Fe-Mn-Si-Cr-Ni shape memory alloys (SMAs) were prepared by mechanical alloying and discharge plasma sintering. The effects of milling time on the microstructure evolution, mechanical properties, superelasticity and corrosion resistance of Fe-Mn-Si-Cr-Ni SMAs (both powder and sintered bulks) were investigated. With the increase in milling time, the alloy powder gradually formed a solid solution with body-centered cubic (BCC) as the main phase. The increase in milling time promoted the phase transition (BCC -> FCC + BCC2) during the sintering of the alloy, and the BCC2 content in the alloy sintered bulks increased with the increase in milling time. The higher the BCC2 content, the higher the yield strength, compressive strength and hardness of the alloy. The BCC2 phase affected the superelasticity of the alloy by changing the yield strength of the alloy, the higher the yield strength, the stronger the superelasticity of the alloy. The A2 alloy had the best superelasticity, with a superelastic strain of 2.8%. The A2 alloy had higher corrosion resistance in NaOH solution than in HCl solution.