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On the micromechanisms of fatigue-crack propagation in aluminum- lithium alloys: Sheet vs. plate material

Conference ·
OSTI ID:5173701
;  [1];  [2]
  1. Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering
  2. Aluminum Co. of America, Alcoa Center, PA (United States). Alcoa Labs.

Micromechanisms influencing the propagation of long (>10 mm) fatigue cracks in aluminum-lithium alloys are examined by specifically comparing crack-growth kinetics in a peak-aged Al-Li-Cu-Zr alloy 2090, processed as 1.6-mm thin (T83) sheet and 12.7-mm thick (T81) plate. It is found that in general crack-growth rates are significantly faster in the sheet material at equivalent stress-intensity levels, due to differences in the role of crack-tip shielding, resulting from crack deflection and consequent crack closure from wedging of fracture-surface asperities. Microstructurally, such differences are related to variations in the degree of recrystallization, grain structure and deformation texture in the two wrought-product forms. 14 refs., 4 figs.

Research Organization:
Lawrence Berkeley Lab., CA (United States)
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
5173701
Report Number(s):
LBL-28244; CONF-900764--4; ON: DE92000926
Country of Publication:
United States
Language:
English