Microvoid formation during shear deformation of ultrahigh strength steels

Cowie, John G.; Azrin, Morris; Olson, Gregory B.

doi:10.1007/bf02647501

Cited by 67 publications

(40 citation statements)

References 5 publications

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“…In a systems design for Co-Ni UHS steel, several methods were applied for improving both toughness and strength synergistically in the steel research group (SRG) consortium centred at Northwestern University. 15,[62][63][64][65][66][67][68] The related design efforts for enhancing both strength and toughness are summarised in Figure 8, which focuses on (i) ductile-brittle transition temperature (DBTT), 69,70 (ii) enhancement of interphase chemical bonding to delay microvoid softening and (iii) transformation toughening. Further, as hydrogen embrittlement can promote brittle intergranular fracture, grain boundary (GB) chemistry optimisation is also a primary requirement as indicated in Figures 7 and 8.…”

Section: Materials By Design: Design Enginementioning

confidence: 99%

“…It is well-established that microvoid nucleation during plastic deformation accelerates ductile fracture via a process of shear localisation, whereby sudden microvoid nucleation destabilises plastic flow by strain location into shear bands. 64,71 However, the quantitative role of fine~0.1-μm scale secondary particle dispersion which nucleate the microvoids is less well-understood. In an optimised microstructure, these small particles correspond to the Zener-pinning particles [72][73][74] acting as the necessary grain refiners.…”

Section: Materials By Design: Design Enginementioning

confidence: 99%

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Cybermaterials: materials by design and accelerated insertion of materials

Xiong

Olson

2016

npj Comput Mater

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Cybermaterials innovation entails an integration of Materials by Design and accelerated insertion of materials (AIM), which transfers studio ideation into industrial manufacturing. By assembling a hierarchical architecture of integrated computational materials design (ICMD) based on materials genomic fundamental databases, the ICMD mechanistic design models accelerate innovation. We here review progress in the development of linkage models of the process-structure-property-performance paradigm, as well as related design accelerating tools. Extending the materials development capability based on phase-level structural control requires more fundamental investment at the level of the Materials Genome, with focus on improving applicable parametric design models and constructing high-quality databases. Future opportunities in materials genomic research serving both Materials by Design and AIM are addressed. BACKGROUND: ICMD BLUEPRINTThe far-reaching multi-agency enterprise, Materials Genome Initiative (MGI), 1,2 highlights computational materials design techniques grounded in fundamental databases, which can support an ambition of decreasing the full development cycle of new materials from the present 10-20 years to ⩽ 5 years. As a subfield of the broader field of integrated computational materials engineering (ICME), which includes modelling of existing materials, 3,4 the MGI centres on design of new materials and their accelerated qualification through the inherent predictability of designed systems. Creation of the infrastructure of this technology has been a global activity as summarised in a recent series of viewpoint papers on materials genomics. 5-10 Particularly notable has been the design work of Bhadeshia 8 at the University of Cambridge and his former students including Harada 11,12 and Reed. 13 The highest achievements of full cycle compression have been demonstrated in US research, which will be the focus of this paper.In the development of applied engineering materials design powered by fundamental thermodynamic and kinetic genomic databases, a hierarchical infrastructure called ICMD presents a proven scenario of materials genomic design for accelerated engineering innovation. As indicated in Figure 1, the backbone of the ICMD infrastructure is composed of Materials by Design and accelerated insertion of materials (AIM) techniques. The application of both techniques spans the entire course of materials innovation, which can be divided into three phases: concept implementation, materials and processing design, and material qualification. The quality of the materials innovation is determined by the mechanistic models applied in the ICMD framework, which follow the universal process-structure-property-performance paradigm in materials science. 14 In Materials by Design, both process-structure and structure-property models are evaluated and refined to maximise the model-predictability grounded in the Materials Genome, which is powered by fundamental research on

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Section: Materials By Design: Design Enginementioning

confidence: 99%

Section: Materials By Design: Design Enginementioning

confidence: 99%

Cybermaterials: materials by design and accelerated insertion of materials

Xiong

Olson

2016

npj Comput Mater

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“…A further development of the top hat was the flat "modified double shear" specimen, which is essentially a radial slice through the cylindrical top hat (Klepaczko 1994;Klepaczko 1998). Other types of double linear shear specimens include the flat doubly-notched bar used earlier by (Campbell & Ferguson 1970), and the modified doubly-notched Charpy specimen of Cowie et al (1989). These adiabatic shear specimens are all designed to restrict plastic deformation to a very narrow gage section, where very high shear strains and strain rates can be achieved under impact loading.…”

Section: Experimental Backgroundmentioning

confidence: 99%

“…The linear shear technique adopted in the early stages of this project was that of Cowie et al (1989). The specimen is a square doubly-notched bar ( Figure 3) whose ends are rigidly clamped while the center section is impacted by a striker.…”

Section: Double Linear Shearmentioning

confidence: 99%

High-Rate Shear Deformation and Failure in Structural Alloys

Dawson¹

2002

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Experiments were conducted to determine the dynamic shear behavior of a wide range of aluminum, titanium, and steel alloys. Principal experimental techniques were the torsional Kolsky bar and the Shear Compression Specimen (SCS) geometry. For the purpose of determining adiabatic shear susceptibility in this range of alloys, it was found that both techniques were unable to induce adiabatic shear in alloys resistant to that failure mode. The SCS geometry has demonstrated a capability for characterizing shear deformation behavior over a wide range of strain rates. For modeling and simulation of adiabatic shear phenomena, an improved adiabatic temperature evolution equation has been implemented. Finite element simulations of the torsional Kolsky and SCS geometries were conducted to evaluate the influence of pre-existing geometric inhomogeneities on adiabatic shear band initiation. 3

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“…In addition, if void nucleation is disregarded, the GTN model cannot describe ductile failure evolution for shear stress close to zero since, according to this constitutive model, the void growth mechanism requires hydrostatic tension within the material. However, continued softening and then ductile failure is known to occur at low triaxiality and even in situations of pure shear [9,10].…”

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confidence: 99%

Ductile Shear Damage Model for Porous Materials

Siad¹,

Gangloff²,

Bohr³

2014

JMSE-B

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Based on a pre-existing yield function, an extended version of the well-known Gurson-Tvergaad-Needleman (GTN)isotropic hardening model is presented in this investigation. The yield function of the proposed constitutive model possesses the distinctiveness to be more accurate for arbitrary void volume fraction and especially to explicitly depend upon the third stress invariant. As a numerical example, the presented constitutive model and, for the purpose of comparison, the GTN model, are used to analyse the necking of a round tensile bar and the two-dimensional simple dynamic shearing problem. The numerical results highlight similarities, good agreement as long as softening initiation of specimen is not reached, and discrepancy as soon as failure of specimen starts, between the proposed model and the GTN model.

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Microvoid formation during shear deformation of ultrahigh strength steels

Cited by 67 publications

References 5 publications

Cybermaterials: materials by design and accelerated insertion of materials

Cybermaterials: materials by design and accelerated insertion of materials

High-Rate Shear Deformation and Failure in Structural Alloys

Ductile Shear Damage Model for Porous Materials

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