The influence of forging and extrusion on the microstructure and martensitic transformation in Ni-Mn-Ga alloys

Open School-Conference of NIS Countries Ultrafine Grained and Nanostructured Materials

Musabirov, I.I.^1 ; Safarov, I.M.^1 ; Galeyev, R.M.^1 ; Abdullina, D.R.^1 ; Koledov, V.V.^2 ; Mulyukov, R.R.^1

Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Khalturina 39, Ufa

450001, Russia^1

Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Mokhovaya 11-7, Moscow

125009, Russia^2

关键词: Bi-modal structures;    Comparative analysis;    Fine-grained structure;    Heusler;    Large-grain;    Low temperature regions;    Martensite transformation temperature;    Ni-Mn-Ga alloys;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/447/1/012024/pdf
DOI  :  10.1088/1757-899X/447/1/012024

来源: IOP

【 摘 要 】

The work presents the comparative analysis of the microstructure and character of martensitic transformation in Heusler Ni-Mn-Ga alloys subjected to plastic deformation by forging and complex treatment by forging with subsequent extrusion. It is shown that the treatment by forging leads to the formation of a bimodal structure with large grains of several micrometres surrounded by a fine-grained structure. After a complex treatment, a bimodal structure is also observed. But the volume fraction of the fine-grained structure is larger than in the previous case. Analysis of the martensite transformation temperature shows that thermomechanical treatment by both methods leads to a slight shift in the martensite transformation temperature to the low temperature region.