Load partitioning between the bcc-iron matrix and NiAl-type precipitates in a ferritic alloy on multiple length scales

• Published in: Scientific reports 2016-03, Vol.6 (1), p.23137-23137, Article 23137
• Main Authors: Sun, Zhiqian, Song, Gian, Sisneros, Thomas A., Clausen, Bjørn, Pu, Chao, Li, Lin, Gao, Yanfei, Liaw, Peter K.
• Format: Article
• Language: English
• Subjects: 639/301/1023/1025; 639/301/1023/1026; 639/301/1023/303; Alloys; Anisotropy; composites; Diffraction; Dislocation; Humanities and Social Sciences; Iron; MATERIALS SCIENCE; Mechanical properties; metals and alloys; multidisciplinary; Neutron Diffraction; Plasticity; Science
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep23137

An understanding of load sharing among constituent phases aids in designing mechanical properties of multiphase materials. Here we investigate load partitioning between the body-centered-cubic iron matrix and NiAl-type precipitates in a ferritic alloy during uniaxial tensile tests at 364 and 506 °C on multiple length scales by in situ neutron diffraction and crystal plasticity finite element modeling. Our findings show that the macroscopic load-transfer efficiency is not as high as that predicted by the Eshelby model; moreover, it depends on the matrix strain-hardening behavior. We explain the grain-level anisotropic load-partitioning behavior by considering the plastic anisotropy of the matrix and elastic anisotropy of precipitates. We further demonstrate that the partitioned load on NiAl-type precipitates relaxes at 506 °C, most likely through thermally-activated dislocation rearrangement on the microscopic scale. The study contributes to further understanding of load-partitioning characteristics in multiphase materials.