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

Personal Author(s) : Scarich,G V ; Bretz,P E ; Bresnahan,K M

PDF Url : ADA180355

Report Date : Dec 1985

Pagination or Media Count : 129

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.

Descriptors :   *AIRFRAMES, *ALUMINUM ALLOYS, *FRACTURE(MECHANICS), *LITHIUM ALLOYS, AIR FORCE RESEARCH, LOADS(FORCES), GRAIN SIZE, BINARY ALLOYS, GRAIN BOUNDARIES, COPPER, LITHIUM, MAGNESIUM, CYCLIC TESTS, LIFE EXPECTANCY(SERVICE LIFE), CHEMISTRY, CONTROL, CRACK PROPAGATION, FATIGUE, FATIGUE(MECHANICS), GRAIN STRUCTURES(METALLURGY), HIGH STRENGTH ALLOYS, LITHIUM, MICROSTRUCTURE, PEAK VALUES, RESISTANCE, SPECTRA, STRESSES, STRUCTURAL PROPERTIES, SURFACES, TENSILE PROPERTIES, TENSION, TEST METHODS, TOUGHNESS

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE