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The influence of the temperature of tensile test on the structure and plastic properties of copper alloy type CuCr1Zr

Ozgowicz W., Kalinowska-Ozgowicz E., Grzegorczyk B.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 29, nr 2

143-146

EN

Purpose: The purpose of this paper is to determine the influence of temperature of plastic deformation on the structure and mechanical properties of copper alloy of the type CuCr1Zr during a tensile test. Design/methodology/approach: The tensile test of the investigated alloy was realized in the temperature range of 20 ÷ 700° C with strain rate of 1.2 • 10 -3 s -1. Metallographic observations of the structure were carried out on a light microscope and the fractographic investigation of fracture on an electron scanning microscope. Findings: The mechanical properties of alloy as well as the range of occurrence of the Portevin - Le Chatelier phenomenon was determined on the basis of σ - ε curves formed by tensile tests; however the character of fracture during the break of the samples was defined on the basis of fractographic investigations. Practical implications: In result of tensile tests of copper alloy it has been found that the PLC effect occurs in temperature range of 250÷400 ° C. However, the ductility minimum temperature of the alloy equals about 550° C. Originality/value: A correlation of temperature of PLC effect was achieved with a qualitative description of the type of "teething" on the σ - ε curves, compatible with the classification quoted in literature.

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Analysis of the Portevin - Le Chatelier effect in tin bronzes at elevated temperatures

Ozgowicz W., Grzegorczyk B.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

281-289

EN

Purpose: The aim of the present paper is the determination of the effect of the chemical composition and temperature of deformation of standardized tin bronzes and bronze modified with zirconium on the Portevin-Le Chatelier (PLC) phenomenon, mainly basing on the shape of stress-strain curves within the temperature range of 100-300° C and observations of their structure. The reasons of the occurrence of such en effect are so far no fully known and explained and the opinions concerning is physical basis vary. Design/methodology/approach: Of essential design in this research is determination of the dependence of PLC effect on the chemical composition, temperature and strain rate and the preliminary heat treatment and grain size. The main method used in this investigation is tensile test at elevated temperature. Findings: The main conclusions are following: the PLC effect on tin bronzes with a micro-addition of zirconium in an amount of 0.01-0.05% depends the temperature of deformation in the tensile test in the range of 100-300° C and the chemical composition of the alloys; the type of serration revealed on the σ-ε curve depend mainly on the temperature of deformation and can be differ during the respective stages of the analyzed curves. Practical implications: In this paper implications for practice are not taken into consideration. Originality/value: In this paper an additive type of serration observed on the curves σ -ε , denoted by the symbol D, is new.

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The influence of the chemical composition and temperature of plastic deformation on the PLC effect in tin bronzes

Ozgowicz W., Opeldus B.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

129--132

EN

Purpose: The aim of the present paper is the determination of the effect of the chemical composition and temperature of deformation of standardized tin bronzes and bronze modified with zirconium on the Portevin-Le Chatelier (PLC) phenomenon, mainly basing on the shape of stress-strain curves within the temperature range of 100÷300°C and observations of their structure. The reasons of the occurrence of such en effect are so far no fully known and explained and the opinions concerning is physical basis vary. Design/methodology/approach: Of essential design in this research is determination of the dependence of PLC effect on the chemical composition, temperature and strain rate and the preliminary heat treatment and grain size. The main method used in this investigation is tensile test at elevated temperature. Findings: The main conclusions are following: the PLC effect on tin bronzes with a miero-addition of zirconium in an amount of 0.01÷0.05% depends the temperature of deformation in the tensile test in the range of 100÷300°C and the chemical composition of the alloys; the type of serration revealed on the δ–ε curve depend mainly on the temperature of deformation and can be differ during the respective stages of the analyzed curves. Practical implications: In this paper implications for practice are not taken into consideration. Originality/value: In this paper an additive type of serration observed on the curves δ–ε, denoted by the symbol D, is new.