Journal ArticleDOI
An investigation of the plastic fracture of AISI 4340 and 18 Nickel-200 grade maraging steels
T. B. Cox,John R. Low +1 more
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In this paper, the authors studied the mechanisms of plastic fracture in high-purity and commercial 18 Ni, 200 grade maraging steels and quenched and tempered AISI 4340 steels.Abstract:
The mechanisms of plastic fracture (dimpled rupture) in high-purity and commercial 18 Ni, 200 grade maraging steels and quenched and tempered AISI 4340 steels have been studied. Plastic fracture takes place in the maraging alloys through void initiation by fracture of titanium carbo-nitride inclusions and the growth of these voids until impingement results in coalescence and final fracture. The fracture of AISI 4340 steel at a yield strength of 200 ksi (1378 MN/mm2) occurs by nucleation and subsequent growth of voids formed by fracture of the interface between manganese sulfide inclusions and the matrix. The growth of these inclusion-nucleated voids is interrupted long before coalescence by impingement, by the formation of void sheets which connect neighboring sulfide-nucleated voids. These sheets are composed of small voids nucleated by the cementite precipitates in the quenched and tempered structures. The sizes of non-metallic inclusions are an important aspect of the fracture resistance of these alloys since the investigation demonstrates that void nuclea-tion occurs more readily at the larger inclusions and that void growth also proceeds more rapidly from the larger inclusions. Using both notched and smooth round tensile specimens, it was demonstrated that the level of tensile stress triaxiality does not effect the void nu-cleation process in these alloys but that increased levels of triaxial tension do result in greatly increased rates of void growth and a concomitant reduction in the resistance to plastic fracture.read more
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Journal ArticleDOI
Analysis of the cup-cone fracture in a round tensile bar
Viggo Tvergaard,Alan Needleman +1 more
TL;DR: In this article, a set of elastic-plastic constitutive relations that account for the nucleation and growth of micro-voids is used to model the failure of a round tensile test specimen.
Book ChapterDOI
Material Failure by Void Growth to Coalescence
TL;DR: In this paper, a convected coordinate formulation of the field equations is used to describe the material failure by coalescence of microscopic voids, and a detailed micromechanical study of shear band bifurcation that accounts for the interaction between neighboring voids and the strongly nonhomogeneous stress distributions around each void has been carried out, and also elaborated in this chapter.
Journal ArticleDOI
Finite deformation analysis of crack-tip opening in elastic-plastic materials and implications for fracture
TL;DR: In this article, a finite element method was used to analyze the deformation field around smoothly-blunting crack tips in both non-hardening and hardening elastic-plastic materials, under contained plane-strain yielding and subject to mode I opening loads.
Journal ArticleDOI
Cavity formation from inclusions in ductile fracture
A. S. Argon,Jay Im,R. Safoglu +2 more
TL;DR: In this article, the authors examined the conditions for cavity formation from equiaxed inclusions in ductile fracture and found that critical local elastic energy conditions are necessary but not sufficient for cavities formation.
References
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Journal ArticleDOI
On the ductile enlargement of voids in triaxial stress fields
James R. Rice,D.M. Tracey +1 more
TL;DR: In this article, a variational principle is established to characterize the flow field in an elastically rigid and incompressible plastic material containing an internal void or voids, and an approximate Rayleigh-Ritz procedure is developed and applied to the enlargement of an isolated spherical void in a nonhardening material.
Journal ArticleDOI
Some observations of void growth during the tensile deformation of a high strength steel
S. Floreen,H.W. Hayden +1 more
Journal ArticleDOI
A critical note on electron fractography
TL;DR: In this article, the possibility to tilt the specimen in the advanced transmission electron microscopes over angles as large as 90° has revealed new evidence on fracture surface features such as fatigue striations and dimple shapes.
Journal ArticleDOI
Carbide Cracking in a High-Strength Steel
S. Floreen,H. W. Hayden +1 more
TL;DR: In this paper, a high-carbon maraging steel has been subjected to four different heat-treatments to vary its tensile properties and the stresses necessary to initiate cracking of TiC particles in the steel were then determined.