Simulation of isothermal precision extrusion of NiTi shape memory alloy pipe coupling by combining finite element method with cellular automaton

• Published in: Journal of Central South University Vol. 24; no. 3; pp. 506 - 514
• Main Authors: Zhang, Yan-qiu, Jiang, Shu-yong, Zhao, Ya-nan, Zhu, Xiao-ming
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.03.2017; Springer Nature B.V
• Subjects: Cellular automata; Coupling; Dynamic recrystallization; Engineering; Extrusion; Finite element analysis; Finite element method; Grain size; Intermetallic compounds; Metallic Materials; Microstructure; Nickel base alloys; Nickel titanides; Pipes; Plastic deformation; Shape memory alloys; shape memory alloy; finite element method; dynamic recrystallization; cellular automaton; extrusion
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-017-3453-5

In order to present the microstructures of dynamic recrystallization (DRX) in different deformation zones of hot extruded NiTi shape memory alloy (SMA) pipe coupling, a simulation approach combining finite element method (FEM) with cellular automaton (CA) was developed and the relationship between the macroscopic field variables and the microscopic internal variables was established. The results show that there exists a great distinction among the microstructures in different zones of pipe coupling because deformation histories of these regions are diverse. Large plastic deformation may result in fine recrystallized grains, whereas the recrystallized grains may grow very substantially if there is a rigid translation during the deformation, even if the final plastic strain is very large. As a consequence, the deformation history has a significant influence on the evolution path of the DRX as well as the final microstructures of the DRX, including the morphology, the mean grain size and the recrystallization fraction.