title: Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing.
abstract: We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium basedin situductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24μm to 5μm) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites.
authors.affiliation: Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, USA.
authors.forename: Harpreet Singh
authors.initials: HS
authors.lastname: Arora
authors.affiliation: Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, USA.
authors.forename: Sanghita
authors.initials: S
authors.lastname: Mridha
authors.affiliation: School of Mechanical, Materials and Energy Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
authors.forename: Harpreet Singh
authors.initials: HS
authors.lastname: Grewal
authors.affiliation: School of Mechanical, Materials and Energy Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
authors.forename: Harpreet
authors.initials: H
authors.lastname: Singh
authors.affiliation: Engineering and Science Directorate, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Hofmann
authors.affiliation: Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, USA.
authors.forename: Sundeep
authors.initials: S
authors.lastname: Mukherjee
keywords: bulk amorphous alloys; nanoindentation; shear bands; thermomechanical processing