Accession Number:

ADA073559

Title:

Development of Improved High Strength Alumiunum Powder Metallurgy Products

Descriptive Note:

Progress rept. no. 2, 1 Jun-31 Dec 1978

Corporate Author:

DEUTSCHE FORSCHUNGS- UND VERSUCHSANSTALT FUER LUFT- UND RAUMFAHRT E V COLOGNE (GERMANY F R)

Personal Author(s):

Report Date:

1978-12-31

Pagination or Media Count:

147.0

Abstract:

An investigation of high strength aluminum 2024 and 7075 alloys was conducted. Both powder metallurgy PM and conventional ingot metallurgy IM extrusion products were examined with particular attention devoted to fatigue behavior. The PM alloys were produced from prealloyed, air atomized powders of various average particle diameters APD using carefully controlled fabrication procedures. The most significant step was a full vacuum preheat treatment of 80 dense compacts which controlled hydrogen contents of the PM products, thereby producing equivalent hydrogen contents in both the PM and IM alloy products. Laboratory ingots were also produced with chemical compositions and processing parameters identical to those of PM products. Notch Kt3 HCF testing R0.1 was conducted to maximize the likelihood that HCF differences, if they occurred, would be statistically and metallurgically significant. Fatigue tests were conducted in lab air to simulate service environment, however, testing frequency 100 Hz would tend to reduce any environmental effect. The products investigated included 1 undirectional, isothermally vacuum hot-pressed 610 MPa with 10 min dwell at 733 K for 7075 and 753 K for 2024 PM billets, and 2 extrusions of the IM and hot-pressed PM billets extrusion - preheat 643 K with 101 and 251 direct extrusion ratios. Extrusion parameters were selected based on the previously reported PM processing study 1.

Subject Categories:

  • Industrial Chemistry and Chemical Processing
  • Inorganic Chemistry
  • Properties of Metals and Alloys
  • Fabrication Metallurgy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE