Metallurgical Factors Controlling Structure in High Strength P/M Products.
Abstract
The effects of process variables upon the structure/property relationships for Al-Zn-Mg-Cu-Co powder metallurgy alloys were investigated. Variations in alloy composition, atomized powder characteristics, hot compacting procedures, hot work operations, and heat treatments were evaluated by tensile, stress corrosion, toughness, and fatigue crack growth rate testing, as well as micro-structural examination. Optimum process steps were identified, resulting in P/M products with properties superior to those of commercial 7000 series ingot alloys. In particular, the P/M MA87 alloy (6.5Zn-2.5Mg-1.5Cu-0.4Co) was found to have increased strength, equal ductility, and substantially higher toughness than 7050 alloy forging of equal stress corrosion resistance. Of special significance was the improved resistance to fatigue crack growth rate of this alloy. P/M MA87 alloy forging fabricated from triple upset and drawn billet demonstrated fatigue crack growth rates 15 to 1000% slower than 7050 alloy forgings. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1976
- Accession Number
- ADA030606
Entities
People
- W. L. Otto Jr.
Organizations
- Alcoa