A model for the anomalous mechanical properties of nickel-base L1{sub 2} ordered alloys. 1: Dislocations dynamics

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(95)00388-6· OSTI ID:264098

Caillard, D; Paidar, V ^[1]

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1. CEMES/CNRS, Toulouse (France)

A new model has been set up with the aim of explaining the mechanical properties of L1{sub 2} nickel base alloys, in particular their anomalous increase of yield-stress with increasing temperature. In agreement with recent microscopic observations, dislocations movements are assumed to be controlled by a series of double cross-slip mechanisms between octahedral and cube planes, leading to formations and destructions of incomplete Kear-Wilsdorf locks. In this first part, the model is two-dimensional, and the splitting of superpartials into Shockley partials is not taken into account. The forces acting on leading and trailing superpartials of incomplete Kear-Wilsdorf locks have been computed, with the aim of studying the kinetics of their evolution under an applied stress. Fairly good values of the flow-stress have been obtained at low and high temperature in Ni{sub 3}Ga, assuming that the ratio of the antiphase boundary (APB) energies in cube and octahedral planes is 0.9, and assuming that the distance of cross-slip onto the cube plane increases with increasing temperature.

• OSTI ID: 264098
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 7 Vol. 44; ISSN XZ504Y; ISSN 1359-6454
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DISLOCATIONS
FLOW STRESS
KINETICS
MECHANICAL PROPERTIES
NICKEL BASE ALLOYS
SLIP
STRAIN HARDENING
TEMPERATURE DEPENDENCE
YIELD STRENGTH