Strain-induced structural changes and chemical reactions. 2: Modelling of reactions in shear band

Journal Article · Fri Oct 09 04:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00214-6· OSTI ID:289505

Levitas, V I ^[1]; Nesterenko, V F; Meyers, M A ^[2]

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1. Univ. of Hannover (Germany). Inst. for Structural and Computational Mechanics
2. Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Applied Mechanics and Engineering Sciences

The problem on strain-induced chemical reaction (SICR) and structural changes (SCs) in a thin layer inside the shear band is formulated and solved for large strains. It is analytically demonstrated that intense plastic deformation can accelerate chemical reactions. The phenomenon of reaction-induced plasticity (RIP), similar to transformation-induced plasticity at phase transitions is derived and modelled. A criterion for athermal SICR is derived and distinctive points of the approach proposed at zero shear stresses and classical chemical thermodynamics are analyzed. Two mechanisms are proposed for the experimentally observed positive effect of shear stresses on SC from the low temperature phase to the high temperature phase. The first one is related to the necessity of fulfillment of the yield condition for the transforming material. The second mechanism is connected with the additional heating due to RIP. A kinetic criterion of chemical reaction is formulated. As an example, the SICR in Ti-Si and Nb-Si mixtures is considered. It is shown that the main reason for acceleration of reaction kinetics due to shear stress or strain is related to the increase of effective temperature due to RIP. The increase of driving force due to shear stresses does not affect the kinetics.

• OSTI ID: 289505
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 16 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL REACTIONS
KINETICS
MATHEMATICAL MODELS
MICROSTRUCTURE
NIOBIUM SILICIDES
STRAINS
THERMODYNAMICS
TITANIUM SILICIDES