skip to main content

DOE PAGESDOE PAGES

Title: In Situ TEM Nanoindentation Studies on Stress-Induced Phase Transformations in Metallic Materials

Though abundant phase transformations are in general thermally driven processes, there are many examples wherein stresses can induce phase transformations. We applied numerous in situ techniques, such as in situ x-ray diffraction and neutron diffraction in order to reveal phase transformations. Recently, an in situ nanoindentation technique coupled with transmission electron microscopy demonstrated the capability to directly correlating stresses with phase transformations and microstructural evolutions at a submicron length scale. We briefly review in situ studies on stress-induced diffusional and diffusionless phase transformations in amorphous CuZrAl alloy and NiFeGa shape memory alloy. Moreover, in the amorphous CuZrAl, in situ nanoindentation studies show that the nucleation of nanocrystals (a diffusional process) occurs at ultra-low stresses manifested by a prominent stress drop. In the NiFeGa shape memory alloy, two distinctive types of martensitic (diffusionless) phase transformations accompanied by stress plateaus are observed, including a reversible gradual phase transformation at low stress levels, and an irreversible abrupt phase transition at higher stress levels.
Authors:
 [1] ;  [2] ;  [3]
  1. Texas A & M Univ., College Station, TX (United States). Materials Science and Engineering; Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology
  2. Texas A & M Univ., College Station, TX (United States). Materials Science and Engineering and Electrical and Computer Engineering
  3. Texas A & M Univ., College Station, TX (United States). Materials Science and Engineering and Mechanical Engineering
Publication Date:
OSTI Identifier:
1304712
Report Number(s):
LA-UR--15-28427
Journal ID: ISSN 1047-4838
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
JOM. Journal of the Minerals, Metals & Materials Society
Additional Journal Information:
Journal Volume: 68; Journal Issue: 1; Journal ID: ISSN 1047-4838
Publisher:
Springer
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE