The influence of thermo-mechanical treatment on phase transformation and shape memory effect of CuAl9Fe4Ni2 alloy

• Published in: Materials research express 2021-10, Vol.8 (10), p.106527
• Main Authors: Khanh, Pham Mai, Tuan, Vu Anh, Nhung, Le Thi, Nam, Nguyen Duong
• Format: Article
• Language: English
• Subjects: Additives; Alloys; Aluminum base alloys; Cold water; Deformation; Deformation effects; detwinner martensite; Grain size; Heat treatment; Iron; Martensite; Martensitic transformations; Nickel; phase transformation; Shape effects; shape memory; Shape memory alloys; TEM; thermo-mechanical treatment; Thermomechanical treatment
• ISSN: 2053-1591; 2053-1591
• DOI: 10.1088/2053-1591/ac3167

Shape memory alloys can return to their original shape by reversible martensitic transformation. The shape memory effect of these alloys has been considered to relate to phase transformation, especially martensite transformation. In the copper-aluminum alloys containing Fe and Ni additives, the relationship between the martensitic transformation and shape memory effect occurs by applying a thermo-mechanical deformation and heat treatment process. This paper presents the phase transformation of the CuAl9Fe4Ni2 alloy that suffered from the deformation and heat treatment process. The samples were heated above 1173°K for homogenization. Then, they were rolled with an appropriate degree of strain to prepare the good conditions for the next steps. They were heated again to 1173°K, then quenched in water to 373°K, and then cooling down in cold water to form martensites with fine grain sizes. Next, the samples underwent cold deformation to create a fine grain in the structure and a favorable distribution for the shape memory process. Finally, the samples were shaped and heated at 843°K to decompose the martensite phase and return to their original shape. The phase transformation and the structure of martensite were determined by modern analytical techniques. The results show that the shape memory level was up to 80%.