Publications de William Curtin

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Twinning is an important deformation mode in lightweight Mg alloys, but the mechanisms of nucleation and growth of twins and their interactions with solutes remain largely unresolved. Here, a new model for thermally-activated, stress-driven growth of twin ...

Solute strengthening in substitutional alloys can be classified into two categories, strong-pinning (Friedel) and weak-pinning (Labusch), each with its own characteristic scaling with concentration and temperature. The transition between the two strengthen ...

A material is intrinsically ductile under Mode I loading when the critical stress intensity K-Ie for dislocation emission is lower than the critical stress intensity K-Ic for cleavage. K-Ie is usually evaluated using the approximate Rice theory, which pred ...

High-entropy alloys are random alloys with five or more components, often near equi-composition, that often exhibit excellent mechanical properties. Guiding the design of new materials across the wide composition space requires an ability to compute necess ...

Cross-slip is a fundamental process of screw dislocation motion and plays an important role in the evolution of work hardening and dislocation structuring in metals. Cross-slip has been widely studied in pure FCC metals but rarely in FCC solid solutions. H ...

Atomistic simulations are a powerful complement to experimental probes for understanding the nanoscale processes associated with the effects of hydrogen (H) on plasticity and fracture that are the underlying causes of hydrogen embrittlement (HE). Current e ...

The rate- and temperature-dependent plastic flow in a material containing two types of thermally activatable obstacles to dislocation motion is studied both numerically and theoretically in a regime of relative obstacle densities for which the zero-tempera ...

Strengthening, i.e. increased stress required to move a dislocation, in dilute or complex alloys arises from the totality of the interaction energies between the solutes and an individual dislocation. Prevailing theories for strengthening in bcc alloys con ...

Hydrogen ingress into a metal is a persistent source of embrittlement. Fracture surfaces are often intergranular, suggesting favorable cleave crack growth along grain boundaries (GBs) as one driver for embrittlement. Here, atomistic simulations are used to ...

Negative strain-rate sensitivity due to dynamic strain aging in Aluminium-5XXX alloys leads to reduced ductility and plastic instabilities at room temperature, inhibiting application of these alloys in many forming processes. Here a hierarchical multiscale ...

Magnesium is an excellent candidate as lightweight structural material, but has strong plastic anisotropy, and the activation of, operation of, and competition between different slip and twinning systems remain active areas of research. Here, the nucleatio ...

Atomistic simulations of bicrystal samples containing a grain boundary are used to examine the effect of hydrogen atoms on the nucleation of intergranular cracks in Ni. Specifically, the theoretical strength is obtained by rigid separation of the two cryst ...

Hydrogen (H) embrittlement in multicomponent austenitic alloys is a serious limitation to their application in many environments. Recent experiments show that the High-Entropy Alloy (HEA) CoCrFeMnNi absorbs more H than 304 Stainless Steel but is less prone ...

Strengthening by needle-shaped precipitates is critical in Al–Mg–Si alloys. Here, the strengthening is studied computationally at the peak-aged condition where precipitate shearing and Orowan looping are usually considered to have equal strengths. Pseudo-r ...

Molecular dynamics simulations of dislocation/obstacle interactions are enhancing our physical understanding of plasticity. However, despite increasing computational power, the interaction between simulation cell boundaries and the long ranged fields of di ...

Many metal alloys are strengthened by controlling precipitation to achieve an optimal peak-aged condi-tion where the strength-limiting processes of precipitate shearing and Orowan looping are thought to be comparable. Qualitative models have long captured ...

Mechanical stress combined with alloying as controlled by CO dissociation is investigated for the control of methanation activity. CO dissociation over strained Ni(211), Ni3Fe(211), and NiFe(112) is investigated. A continuous 0.62 eV range of CO reaction e ...

The face-centered cubic medium-entropy alloy NiCoCr has received considerable attention for its good mechanical properties, uncertain stacking fault energy, etc, some of which have been attributed to chemical short-range order (SRO). Here, we examine the y ...

High-strength metal alloys achieve their performance via careful control of precipitates and solutes. The nucleation, growth, and kinetics of precipitation, and the resulting mechanical properties, are inherently atomic scale phenomena, particularly during ...

The thermally activated pyramidal-to-basal (PB) transition of (c + a) dislocations, transforming glissile pyramidal dissociated core structures into sessile basal dissociated ones, lies at the origin of low ductility in pure magnesium (Mg). Solute-accelera ...

William Curtin

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A New Mechanism for Twin Growth in Mg Alloys

Friedel vs. Labusch: the strong/weak pinning transition in solute strengthened metals

New theory for. Mode I crack-tip dislocation emission

First-principles-based prediction of yield strength in the RhIrPdPtNiCu high-entropy alloy

Dislocation cross-slip in fcc solid solution alloys

The role of atomistic simulations in probing hydrogen effects on plasticity and embrittlement in metals

Thermally activated plastic flow in the presence of multiple obstacle types

Solute/screw dislocation interaction energy parameter for strengthening in bcc dilute to high entropy alloys

Atomistic study of hydrogen embrittlement of grain boundaries in nickel: I. Fracture

Quantum-to-continuum prediction of ductility loss in aluminium-magnesium alloys due to dynamic strain aging

Deformation modes in magnesium (0001) and (0 1 -1 1) single crystals: simulations versus experiments

Atomistic study of hydrogen embrittlement of grain boundaries in nickel: II. Decohesion

First principles study of the effect of hydrogen in austenitic stainless steels and high entropy alloys

Modeling peak-aged precipitate strengthening in Al–Mg–Si alloys

Analysis of spurious image forces in atomistic simulations of dislocations

Modeling of precipitate strengthening with near-chemical accuracy: case study of Al-6xxx alloys

Mechanical Stress Combined with Alloying May Allow Continuous Control Over Reactivity: Strain Effects on CO Dissociation and Subsequent Methanation Catalysis over Ni(211), Ni3Fe(211), and NiFe(112)

Yield strength and misfit volumes of NiCoCr and implications for short-range-order

Machine learning for metallurgy I. A neural-network potential for Al-Cu

Designing high ductility in magnesium alloys