Mechanism of Enhanced Toughness in Martensitic Alloys.
Abstract
The objective of this program was to establish the role of heat treatment parameters on the fracture toughness of ultrahigh strength alloys. Microstructural examination and plane strain fracture toughness tests were conducted on alloys 4340 and silicon modified 4340. Heat treatments included both direct as well as step quench schedules. Solutioning temperatures ranged from 870 to 1200 C, and step quenching temperatures ranged from 300 C to 1100 C. Holding times at these temperatures varied from 10 seconds to 2 hours. Tempering temperatures ranged from the as quenched condition to 350C. Valid plane strain fracture toughness results of over 90,000 psi were achieved for alloy 4340 and values of 85,000 psi were achieved for silicon modified 4340 at ultimate strength levels of over 300,000 psi for both alloys. This report covers the first year's results of the two year program. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 20, 1977
- Accession Number
- ADA040373
Entities
People
- W. E. Wood