Accession Number:

ADA180355

Title:

Fatigue Crack-Growth Resistance of Aluminum Alloys Under Spectrum Loading. Volume 2. Aluminum Lithium Alloys.

Descriptive Note:

Final technical rept. 30 Sep 82-31 Mar 85,

Corporate Author:

NORTHROP CORP HAWTHORNE CA AIRCRAFT GROUP

Report Date:

1985-12-01

Pagination or Media Count:

129.0

Abstract:

The objective of this program is to develop metallurgical guidelines and test methodologies for selection and development of spectrum fatigue-resistant, high-strength aluminum alloys of aircraft structural application. This volume II describes the results of characterizations of six experimental alloys containing substantial amounts of lithium. Chemistry, temper, and grain structure were varied to produce systematically controlled microstructures. The six alloys were characterized for chemically composition, microstructure, tensile properties, and fracture toughness. Fatigue crack propagation FCP tests were conducted on specimens of each alloy for both constant-amplitude loading and two F-18 load spectrums. One of the spectrums was dominated by tension loads TD and the other spectrum contained tension and compression loads TC of nearly equal magnitude. The spectrum FCP testing was performed at the maximum peak stress of 145 MPa 21 ksi. Pertinent fracture surface features were documented on the spectrum fatigue specimens.

Subject Categories:

  • Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE