Combined macroscopic and microscopic approach to the fracture of metals. Comprehensive progress report, 1979-1985
Effective finite element procedures for fully plastic crack analysis have been developed. The solutions obtained satisfy stringent consistency relations. They are a key ingredient in the engineering analysis of loss of stability by crack growth of flawed structures. For the prediction of crack growth rates under high temperature conditions, small and finite-deformation solutions have been obtained for the analysis of time-dependent stress and strain fields associated with the sudden loading of tensile cracks in elastic-nonlinear viscous materials. A relationship was developed between flow localization and void nucleation and growth, useful in certain cases of failure by shear localization. Finite strains numerical analysis gives an initial picture of shear-based development at a critical crack tip. In accounting for the variation of plane strain fracture toughness with heat treatment of AISI 4340 steels, it was shown that particle spacing is of primary importance in controlling toughness. A comprehensive model was developed for void nucleation at particle-matrix interfaces in particle strengthened steels. A study of deformation and fracture of dual-phase steels has shown that their exceptional ductility is related to the unfavorable conditions of void initiation and growth at deforming martensite particles. Thermodynamic models, which describe cohesion loss at interfaces due to absorption, can be applied to the transition from brittle to ductile behavior of polycrystals. In 1015 and 1045 steels, hydrogen accelerates the processes of void initiation and void growth without changing the actual mechanism of rupture.
- Research Organization:
- Brown Univ., Providence, RI (USA). Div. of Engineering
- DOE Contract Number:
- AC02-80ER10556
- OSTI ID:
- 5111770
- Report Number(s):
- DOE/ER/10556-105; ON: DE86002286
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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