Accession Number:

ADA030606

Title:

Metallurgical Factors Controlling Structure in High Strength P/M Products.

Descriptive Note:

Final technical rept. Apr 74-Oct 75,

Corporate Author:

ALUMINUM CO OF AMERICA ALCOA CENTER PA ALCOA TECHNICAL CENTER

Personal Author(s):

Report Date:

1976-05-01

Pagination or Media Count:

114.0

Abstract:

The effects of process variables upon the structureproperty 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 PM products with properties superior to those of commercial 7000 series ingot alloys. In particular, the PM 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. PM MA87 alloy forging fabricated from triple upset and drawn billet demonstrated fatigue crack growth rates 15 to 1000 slower than 7050 alloy forgings. Author

Subject Categories:

  • Properties of Metals and Alloys
  • Fabrication Metallurgy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE