Design of Advanced Steels for Armor Applications
Abstract
An interdisciplinary research effort has addressed the fundamental principles for the design of fracture-tough, stress-corrosion resistant, ultrahigh-strength martensitic steels for advanced armor applications. Three alloy compositions, designated MTL1, MTL2, and MTL3 were derived from thermodynamics-based computer-aided design using the THERMOCALC thermochemical database and software system. Hardness and K sub IC fracture toughness were measured as a function of solution treatment temperature and tempering time at 482 deg C, and undissolved carbides were examined by analytical electron microscopy. Although the as-received carbon contents for alloys MTL2 and MTL3 exceeded the design carbon content by .03 wt. pct., optimum heat treatment for alloy MTL2 produced R sub C 56.2 with 69.4 ksi sq root of in toughness, and RC56.4 with 66.3 ksi sq root of in for MTL3. The carbon content of MTL1 fell short by .06 wt. pct., producing a hardness of RC 55.2 at 82.2 ksi sq root of in. Despite the low carbon content, the hardness achieved in the latter case demonstrates the effectiveness of small V additions in enhancing strength in these alloys. Ballistic testing is recommended. Based on the prototype alloy evaluations, iterative design calculations predict improved compositions. Further toughness enhancement should be achievable with a carbon content of 0.25 wt. pct., and by exploitation of multistep tempering treatments to achieve transformation toughening. Armor steels, Secondary hardening steels, Fracture toughness.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1990
- Accession Number
- ADA284361
Entities
People
- Gregory B. Olson
- Timothy A. Stephenson
Organizations
- Northwestern University