Modeling, Characterization, & Thermo-Mechanical Processing of Low-Cost Martensitic Steels

Abstract

Ultra-High Strength Steels (UHSSs) have attracted increasing interest for their use in auto and aerospace industry, mining, and defense applications due to their very high yield strengths and reasonable ductility. However, many of these, such as AerMet-100 and AF1410, are quite expensive making their widespread use cost prohibitive. AFRL scientists have recently developed relatively inexpensive UHSSs, i.e. ES-1 and AF96, however, to make them truly competitive with the commercial UHSSs, their mechanical properties need to be further improved. In a previous study, in collaboration with AFRL scientists, we investigated the effect of Equal Channel Angular Processing (ECAP) on ES-1 UHSS. It was found that under the correct processing parameters, ES-1 after ECAP could demonstrate both ultra-high strength (UTS = 1979 MPa) and respectable ductility (sf = 15%). In the present work, the goal is to develop a fundamental understanding of severe thermo-mechanical processing on mechanical response of low cost epsilon carbide hardening UHSSs. In particular, we aim at discovering new severe plastic deformation approaches to increase the strength and toughness of next generation (AF96, etc.) high performance epsilon carbide steels to the levels greater than 2 GPa, and perform analysis into sub-micron scale grain structures to determine novel mechanisms to increase the strength of lowcost steel formulations. In particular, the role of severe plastic deformation, thermo-mechanical processing and relationships between evolved microstructures and mechanical properties will be investigated in low cost epsilon carbide steels using a suite state-of-the-art experiments.

Document Details

Document Type
DoD Grant Award
Publication Date
May 25, 2017
Source ID
FA86511710003

Entities

People

  • Ibrahim Karaman

Organizations

  • Air Force Research Laboratory
  • Texas Engineering Experiment Station
  • United States Air Force

Tags

Fields of Study

  • Materials science

Readers

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Technology Areas

  • Space