Phase diagram of FeNiCoAlTaB ferrous shape memory alloy on aging time

Zhijian Zhou,Jian Cui,Xiaobing Ren

doi:10.1063/1.4982695

Abstract

Ferrous shape memory alloy, Fe41Ni28Co17Al11.5Ta2.5B0.05, has shown large superelastic strain and strength in previous study. In the fabrication of this alloy, aging process is crucial for the formation of shape memory effect/superelasticity. However, its phase evolution on aging time is not clearly known. In this study, we systematically studied the phase diagram of this alloy on aging time. It is found that the unaged alloy shows a strain glass transition. With the aging time proceeding, the martensitic transformation gradually emerges. The phase diagram can be explained by the formation of coherent precipitates induced by aging. The heterogeneous strain between coherent precipitates and matrix is the driving force responsible for the emerging martensitic transformation. The generic explanation is supposed to be useful in martensitic transformation engineering for developing novel shape memory alloys from non-transforming materials.

Highlights

Metallic alloys with shape memory effect/superelasticity have many applications in the fields of aircraft, automobile, robotics, actuator, orthopedics, dentistry, etc
Though many metallic alloys exhibit martensitic transformation,[1,2,3,4,5,6] very few of them can be used in practical applications utilizing shape memory effect or superelasticity, because some of them exhibit non-thermoelastic martensitic transformation or their superelastic strains are too small to be useful
The phase diagram can be explained by the formation of coherent precipitates induced by aging

Summary

Introduction

Metallic alloys with shape memory effect/superelasticity have many applications in the fields of aircraft, automobile, robotics, actuator, orthopedics, dentistry, etc. Phase diagram of FeNiCoAlTaB ferrous shape memory alloy on aging time Phase diagram of FeNiCoAlTaB ferrous shape memory alloy on aging time Zhijian Zhou,[1] Jian Cui,1,a and Xiaobing Ren1,2 1Multi-Disciplinary Materials Research Center, Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710054, China 2Ferroic Physics Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan (Received 5 January 2017; accepted 17 April 2017; published online 26 April 2017)

Results

Conclusion