COPPER ALLOYS – EARLY APPLICATIONS AND CURRENT PERFORMANCE – ENHANCING PROCESSES Edited by Luca Collini Copper Alloys – Early Applications and Current Performance – Enhancing Processes Edited by Luca Collini Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Iva Simcic Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published February, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Copper Alloys – Early Applications and Current Performance – Enhancing Processes, Edited by Luca Collini p. cm. ISBN 978-953-51-0160-4 Contents Preface VII Part 1 Introduction to the Copper Alloys 1 Chapter 1 Copper and Copper Alloys: Casting, Classification and Characteristic Microstructures 3 Radomila Konečná and Stanislava Fintová Chapter 2 Interaction of Copper Alloys with Hydrogen 31 I. Peñalva, G. Alberro, F. Legarda, G. A. Esteban and B. Riccardi Part 2 Development of High-Performance Current Copper Alloys 49 Chapter 3 Properties of High Performance Alloys for Electromechanical Connectors 51 H A. Kuhn, I. Altenberger, A. Käufler, H. Hölzl and M. Fünfer Chapter 4 Lead-Free Wrought Copper Alloys for Bushings and Sliding Elements 69 Kai Weber and H A. Kuhn Chapter 5 Mechanical Properties of Copper Processed by Severe Plastic Deformation 93 Ludvík Kunz Chapter 6 Fatigue Crack Resistance of Ultrafine-Grained Copper Structures 127 Luca Collini Part 3 Archaeometallurgy of Copper Alloys 151 Chapter 7 Bronze in Archaeology: A Review of the Archaeometallurgy of Bronze in Ancient Iran 153 Omid Oudbashi, S. Mohammadamin Emami and Parviz Davami Preface The use of copper and its alloys by humans goes back thousands of years. Probably copper is the most ancient metal extracted and processed by mankind. With good strength and ductility, ease of processing and good availability, copper has been for millennia an excellent material for creating objects, jewelry and tools of daily use or components with high technological content. Nowadays, copper is used in its pure state mostly in applications that require high heat or electric conductivity, while its alloys (bronzes and brasses) are widely used in several fields thanks to their excellent corrosion and wear resistance. Copper and its alloys have been and still are a great natural resource for the growth of mankind. This book collects, without the claim to be exhaustive, the most recent contributions of engineers and scientists who perform research on this material. These contributions cover two main topics: the development and application of advanced techniques of analysis of ancient relics made of copper, and the application of recently studied alloys, enhanced in mechanical and environmental performances. In my opinion the contrast of this two topics is fascinating in its own way. In order to facilitate its reading, the book has been rationally divided into three distinct sections. The first section contains two papers, the first on the classification of copper and its alloys according to the modern systems, the second on the basic mechanism of interaction of copper with hydrogen. The second section includes four contributions, two on the properties of alloys specifically developed for high-performance electromechanical connectors and for sliding elements, and two on the study of static and fatigue properties of copper subjected to a severe plastic deformation process. The third section includes two very interesting contributions on the archaeometallurgy of copper. Sure that all these high-level contributions are of interest, I would like now to extend my sincere thanks to all those who contributed to the drafting of this book, and in particular to prof. R. Konecna and dr. L. Kunz for their kind assistance. Dr. Luca Collini, Department of Industrial Engineering, University of Parma Italy Part 1 Introduction to the Copper Alloys [...]... Fig 4 Pure copper, chemically polished Copper and Copper Alloys: Casting, Classification and Characteristic Microstructures 7 c) microstructure of wrought Cu with uniform polyhedral grains and annealing twins, white light d) the same microstructure of wrought Cu, polarized light Fig 4 Pure copper, chemically polished 8 Copper Alloys – Early Applications and Current Performance – Enhancing Processes... poured, and give high-grade castings 10 Copper Alloys – Early Applications and Current Performance – Enhancing Processes in the sand, permanent mold, plaster, die, and centrifugal casting processes With highshrinkage alloys, careful design is necessary to promote directional solidification, avoid abrupt changes in cross section, avoid notches (by using generous fillets), and properly place gates and risers;... properties, corrosion resistance and are easily polishable One of the oldest alloys are alloys of 60 % of copper and from 14 to 18 % of nickel content; they were used for decorative and useful objects These alloys have many different commercial names, for example “pakfong”, “alpaca”, “argentan” etc they are used 24 Copper Alloys – Early Applications and Current Performance – Enhancing Processes in the building... polarized light, etched K2Cr2O7 Copper and Copper Alloys: Casting, Classification and Characteristic Microstructures a) (´) microstructure with Pb particles showed as dark gray, etched K2Cr2O7 b) the same microstructure after chemical etching Fig 10 Leaded brass, 42 % of Zn and 2 % of Pb 21 22 Copper Alloys – Early Applications and Current Performance – Enhancing Processes a) polyhedral grains of... chemically etched b) size and orientation of grains, polarized light, etched K2Cr2O7 Fig 7 Deep-drawing brass with 70 % Cu 17 18 Copper Alloys – Early Applications and Current Performance – Enhancing Processes a) (´) microstructure, chemically etched b) α phase is violet, polarized light, etched K2Cr2O7 Fig 8 Brass with 37 % of Zn Copper and Copper Alloys: Casting, Classification and Characteristic Microstructures... silicon and nickel Silicon improves the materials resistance against corrosion and nickel improves the materials ductility Brasses heat treatment Recrystallization annealing is brasses basic heat treatment process Combination of recrystallization annealing and forming allows to change the materials grain 16 Copper Alloys – Early Applications and Current Performance – Enhancing Processes structure and to... 1.2.3 Pure copper and high copper alloys Commercially pure copper and high copper alloys are very difficult to melt and they are very susceptible to gassing Chromium copper melting is negatively linked with oxidation loss of chromium To prevent both oxidation and the pickup of hydrogen from the atmosphere copper and chromium copper should be melted under a floating flux cover In the case of pure copper. .. conditions (R F Schmidt & D G Schmidt, 1997) 14 Copper Alloys – Early Applications and Current Performance – Enhancing Processes 2 Copper based alloys 2.1 Brasses Brasses are copper based alloys where zinc is the main alloying element Besides zinc, also some amount of impurities and very often some other alloying elements are present in the alloys The used alloying elements can improve some properties,... very different sizes Wrought copper microstructure consists of uniform polyhedral grains with similar grain size and it is also possible to observe annealing twins (Fig 4c-e) Because of coppers reactivity, the dangers of surface cracking, porosity, and the formation of internal cavities are high 6 Copper Alloys – Early Applications and Current Performance – Enhancing Processes a) microstructure of... (from 10 to 20 %) and Sn addition (from 5 to 10 %) and also high-leaded bronzes (from 25 to 30 %) without 26 Copper Alloys – Early Applications and Current Performance – Enhancing Processes tin At present, specially leaded bronzes CuSn10Pb and CuSn10Pb10 like bearing bronzes are used (Skočovský et al., 2000, 2006) Lead (additive from 4 to 25 %) improves bearing sliding properties, and tin (from 4 to . COPPER ALLOYS – EARLY APPLICATIONS AND CURRENT PERFORMANCE – ENHANCING PROCESSES Edited by Luca Collini Copper Alloys – Early Applications and Current Performance –. poured, and give high-grade castings Copper Alloys – Early Applications and Current Performance – Enhancing Processes 10 in the sand, permanent mold, plaster, die, and centrifugal casting processes of wrought Cu, polarized light Fig. 4. Pure copper, chemically polished Copper Alloys – Early Applications and Current Performance – Enhancing Processes 8 e) detail of wrought Cu grains,