Macroscopic criteria for the deformation and fracture of iron based alloys

Dina V Orlova,Alexey G Lunev,Lidiya V Danilova,Lev B Zuev

doi:10.3221/igf-esis.42.31

Abstract

In the article the deformation of different steels is analyzed using the autowave theory of plasticity. The article considers the possible use of an autowave model to formulate criteria for the structural strength of materials and elastic-plastic transition. The time and place of future fracture for steel samples are shown can be predicted before visible necking takes place by using the kinetic dependencies of localized plasticity domains at the prefracture stage. The results show that during elastic-plastic transition in lowcarbon steel, there is the break of the curve for the ultrasound velocity versus deformation, which can serve as an acoustic criterion of irreversible deformation for the pressure treatment of metals, the operation and nondestructive testing of products and structures.

Highlights

A t present, the critical parts and structures of many hazardous production facilities operate under mechanical loads which initiate the occurrence and accumulation of damages leading to the fracture of equipment
Since the localized development of a plastic flow has a significant effect on the strength and plastic characteristics of structural steel products, it is of importance to describe the kinetics of a plastic flow and the transition from deformation to ductile fracture
The deformation of metals and alloys is locally developed at all stages of a plastic flow, including elastic-plastic transition

Summary

Introduction

A t present, the critical parts and structures of many hazardous production facilities operate under mechanical loads which initiate the occurrence and accumulation of damages leading to the fracture of equipment. These damages can be timely identified and eliminated if appropriate technical means and methods are available. At present a deformable material is considered to be a nonlinear medium, an appropriate description of which is impossible without the approach based on the concepts for the mechanics of nonlinear media, synergetics and nonlinear acoustics. The stationary structure of zones (stable dissipative systems) corresponds to the stages of parabolic hardening

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