Abnormal strain evolution of austenite upon martensitic transformation in FeNiCo alloy with invar effect : An in situ study

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

1 Scopus Citations
View graph of relations


  • Xiangxiang Rao
  • Yadong Ru
  • Fangmin Guo
  • Lishan Cui
  • Kaiyuan Yu


Original languageEnglish
Article number114942
Journal / PublicationScripta Materialia
Online published25 Jul 2022
Publication statusPublished - Nov 2022


The lattice strain evolution is essential for the understanding of the invar effect. In this letter, the transformation behavior and lattice strain of austenite in a Fe66Ni29Co5 alloy is studied by in situ synchrotron X-ray diffraction during cooling. An abnormal increase of the lattice strain is observed upon martensitic transformation. The strain inhomogeneity is found to increase monotonically before transformation during cooling. The anomalies are suggested to be related to the restricted nature of the transformation, which is further evidenced by the abnormal lattice strain evolution in a laminated Cu/steel nanocomposite.

Research Area(s)

  • Internal stress, Invar alloy, Lattice strain, Martensitic transformation