The correlation of local deformation and stress-assisted local phase transformations in MMC foams

• Published in: Materials characterization Vol. 107; pp. 139 - 148
• Main Authors: Berek, H., Ballaschk, U., Aneziris, C.G., Losch, K., Schladitz, K.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2015
• Subjects: Algorithms; AMPLITUDES; AUSTENITIC STEELS; BACKSCATTERING; CERAMICS; COMPRESSION; COMPUTERIZED TOMOGRAPHY; Correlation; CORRELATIONS; CROSS SECTIONS; DEFORMATION; DUCTILITY; EBSD; Electron back scatter diffraction; ELECTRON DIFFRACTION; Image analysis; In situ XCT; MAGNESIUM OXIDES; Martensitic stainless steels; MARTENSITIC STEELS; MATERIALS SCIENCE; Metal matrix composites; METALS; Mg-PSZ ceramic; MMC foam; PHASE STUDIES; PHASE TRANSFORMATIONS; STRESSES; Structural steels; TRIP steel; ZIRCONIUM OXIDES; In situ XCT; Mg-PSZ ceramic; Image analysis; TRIP steel; MMC foam; EBSD
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2015.06.020

Cellular structures are of growing interest for industry, and are of particular importance for lightweight applications. In this paper, a special case of metal matrix composite foams (MMCs) is investigated. The investigated foams are composed of austenitic steel exhibiting transformation induced plasticity (TRIP) and magnesia partially stabilized zirconia (Mg-PSZ). Both components exhibit martensitic phase transformation during deformation, thus generating the potential for improved mechanical properties such as strength, ductility, and energy absorption capability. The aim of these investigations was to show that stress-assisted phase transformations within the ceramic reinforcement correspond to strong local deformation, and to determine whether they can trigger martensitic phase transformations in the steel matrix. To this end, in situ interrupted compression experiments were performed in an X-ray computed tomography device (XCT). By using a recently developed registration algorithm, local deformation could be calculated and regions of interest could be defined. Corresponding cross sections were prepared and used to analyze the local phase composition by electron backscatter diffraction (EBSD). The results show a strong correlation between local deformation and phase transformation. [Display omitted] •In situ compressive deformation on MMC foams was performed in an XCT.•Local deformation fields and their gradient amplitudes were estimated.•Cross sections were manufactured containing defined regions of interest.•Local EBSD phase analysis was performed.•Local deformation and local phase transformation are correlated.