Micromechanical modeling of temperature-dependent initiation fracture toughness in advanced aluminum alloys
- Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering
- NASA Langley Research Center, Hampton, VA (United States)
The temperature dependence of the plane-strain initiation fracture toughness (K{sub JICi}) is modeled micromechanically for a variety of advanced aluminum alloys that fail by microvoid processes. Materials include precipitation-hardened ingot metallurgy, spray formed, submicron-grain-size powder metallurgy, and metal-matrix composite alloys. A critical-plastic-strain-controlled model, employing tensile yield strength, elastic modulus, work hardening, and reduction of area measurements, successfully predicts K{sub JICi} versus temperature for eight alloys, providing a strong confirmation of this approach. Modeling shows that K{sub JICi} is controlled by the interplay between the temperature dependencies of the intrinsic failure locus {bar {var_epsilon}}{sub f}{sup p}({sigma}{sub m}/{sigma}{sub fl}) and the crack-tip stress/strain fields governed by alloy flow properties. Uncertainties in {bar {var_epsilon}}{sub f}{sup p}({sigma}{sub m}/{sigma}{sub fl}), as well as the critical distance (volume) for crack-tip damage evolution, hinder absolute predictions of K{sub JICi}. Critical distance (calculated from the model) correlates with the nearest-neighbor spacing of void-nucleating particles and with the extent of primary void growth determined from quantitative fractography. These correlations suggest a means to predict absolute plane-strain fracture toughness.
- OSTI ID:
- 624252
- Report Number(s):
- CONF-950618-; ISBN 0-8031-2413-9; TRN: IM9820%%220
- Resource Relation:
- Conference: 27. ASTM symposium on fatigue and fracture mechanics, Williamsburg, VA (United States), 26-29 Jun 1995; Other Information: PBD: 1997; Related Information: Is Part Of Elevated temperature effects on fatigue and fracture; Piascik, R.S. [ed.] [NASA Langley Research Center, Hampton, VA (United States)]; Gangloff, R.P. [ed.] [Univ. of Virginia, Charlottesville, VA (United States)]; Saxena, A. [ed.] [Georgia Inst. of Tech., Atlanta, GA (United States)]; PB: 234 p.; ASTM special technical publication, 1297
- Country of Publication:
- United States
- Language:
- English
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