On the martensitic structure and hardness in as-quenched Fe-Ni alloys

The martensitic transformation in dilute Fe-Ni alloys was firstly investigated by using a composition gradient in the range from 0 to 31 mass% Ni. The current study exhibited the transformation of austenite to equiaxed or acicular ferrite at lower Ni contents can be suppressed and lath martensite can form. The electron backscattered diffraction results showed Ni has important effect on misorientation distribution in martensite. With the increase of Ni content up to similar to 27.5 mass%, the misorientation distributions above 15 degrees increased, and a peak at around 7 degrees gradually disappeared. With the further increase of Ni content, two peaks between about 50 degrees and 60 degrees at low Ni contents changed into three peaks at high Ni contents and a new peak at around 17 degrees arose due to formation of plate martensite. Moreover, it was observed that both block and sub-block was refined with increasing Ni content. Moreover, the micro-hardness/strength of martensitic Fe-Ni alloys between previous works and this work and the micro-hardness of martensite between Fe-C and Fe-Ni alloys were compared and discussed. (C) 2017 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the martensitic transformation in dilute Fe-Ni alloys with a composition gradient, revealing the significant influence of Ni content on misorientation distribution in martensite. Increasing Ni content led to changes in misorientation peaks and refinement of block and sub-block structures, ultimately affecting the micro-hardness and strength of the alloys.