Deformation-Induced Austenite-to-Martensite Transformation in High Stregth Ni-containing Navy Steel
Abstract
A three-year research effort is proposed to examine the fundamentals of the austenite transformation into martensite during deformation in high strength Ni steels of relevance to Naval applications; various aspects of such steels including process development, microstructural evolution, deformation response and weldability are currently under investigation in multiple research groups supported by grants from the Office of Naval Research (Naval Surface Warfare Center, Carderock, MD, Naval Research laboratories in Washington D.C., Brown University, Northwestern University and Lehigh University). In a one-day workshop on this subject, hosted in April 2015 by Dr. Jie Zhang at NSWC-CD, it became abundantly clear that understanding microstructure evolution as a function of processing and deformation is not well-understood and fundamental effort is needed in this direction. This proposal aims to address some of these aspects. In this effort, we plan to systematically characterize the austenite in each step through a combination of techniques and understand the mechanical behavior of such microstructures through small-scale testing. We propose to use a suite of characterization techniques to accomplish this including SEM, in conjunction with EBSD and EDX, TEM (BF and CDF) in conjunction with diffraction and EDX, Mossbauer Spectroscopy, and APT in collaboration with Prof, Seidman at NWU. In-situ heating and straining in the TEM will enable us to understand better the austenite/martensite microstructure evolution as a function of temperature and strain. Small-scale testing will be performed using nanoindentation as well as micropillars that are FIBmachined out from specific microstructural regions of interest and tested in compression to obtain stress-strain curves. Post deformation TEM lift out will enable characterization of the deformation structure in the micropillars.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 03, 2016
- Source ID
- N000141612286
Entities
People
- Sharvan Kumar
Organizations
- Brown University
- Office of Naval Research
- United States Navy