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ASHBY & FROST Perspectives in Creep Fracture
ASHWORTH Ion Implantation into Metals
BARRETT & MASSALSKI Structure of Metals, 3rd Edition
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FROST & ASHBY Deformation-Mechanism Maps
GIFKINS Strength of Metals and Alloys
(3 Volume Set)
HARRIS Mechanical Working of Metals
JOHNSON Plane Strain Slip Line Fields for Metal
Deformation Processes
MANN Bibliography on the Fatigue of Materials,
Components & Structures, Volume 3,
1961-1965
MILLER Mechanical Behaviour of Materials
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NIKU LARI Shot Peening
OSGOOD Fatigue Design, 2nd Edition
SIH Progress in Fracture Mechanics
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Materials Research Bulletin
Metals Forum
Scripta Metallurgica
The Physics of Metals & Metallography
Specialty Steels
and
Hard Materials
Proceedings of the International Conference on
Recent Developments in Specialty Steels and Hard Materials
(Materials Development '82)
held in Pretoria, South Africa, 8-12 November 1982
Edited by
N. R. COMINS and J. B. CLARK
Council for Scientific & Industrial Research, Pretoria, South Africa
PERGAMON PRESS
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Copyright © 1983 Pergamon Press Ltd.
All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system or transmitted in any
form or by any means: electronic, electrostatic, magnetic tape,
mechanical, photocopying, recording or otherwise, without
permission in writing from the publishers.
First edition 1983
Library of Congress Cataloging in Publication Data
International Conference on Recent Developments in
Specialty Steels and Hard Materials (1982: Pretoria,
South Africa)
Specialty steels & hard materials.
Includes index.
1. Steel —Congresses. 2. Heat resistant materials —
Congresses. I. Comins, N. R. II. Clark, J. B.
III. Title.
TA472.I57 1982 620.1'7 83-2410
British Library Cataloguing in Publication Data
International Conference on Recent Developments
in Specialty Steels and Hard Materials
(1982 Pretoria)
Specialty steels & hard materials.
1. Steel —Congresses
I. Title II. Comins, N.R. III. Clark, J.B.
669'.142 TN730
ISBN 0-08-029358-1
In order to make this volume available as economically and as
rapidly as possible the authors' typescripts have been
reproduced in their original forms. This method unfortunately
has its typographical limitations but it is hoped that they in no
way distract the reader.
Printed in Great Britain by A. Wheaton & Co. Ltd., Exeter
Preface
Materials Development '82 took place from 8-12 November 1982 in Pretoria,
South Africa. This International Conference provided a forum for scientists,
engineers and technologists to discuss recent research and development in
the fields of specialty steels and hard metals. The Conference was held
under the auspices of IUPAP (International Union of Pure and Applied Physics)
and the high pressure section was under the sponsorship of AIRAPT (Internat-
ional Association for the Advancement of High Pressure Science and Tech-
nology) .
South Africa is well known internationally as a major exporter of many
important raw materials including chromium, vanadium, manganese, etc.,
some of which, such as chromium, are now regarded as strategic in many
countries. There has been continuing development over the years to market
these materials in ever more processed forms, and attention is now focussed
on the next step in the 'Materials Life Cycle', viz., engineering materials,
including novel ones particularly suited to local production. This confer-
ence was the first International meeting of its kind in South Africa and
was particularly valuable in illustrating the importance of Materials
Science and Engineering. The meeting was attended by some 270 delegates
including visitors from Germany, Israel, Japan, Republic of China, Sweden,
Switzerland, U.K., U.S.A., Zambia and Zimbabwe.
The programme included thirteen invited plenary lectures and thirty-six
contributed research papers, all presented orally. The keynote lecturers
were invited by the Organising Committee with the idea of surveying a range
of aspects in each topic. The focus was on structure-property relationships
with the intention of strengthening the link between the understanding of
microstructural detail, alloy design, processing technology and applications,
as well as including aspects of economic viability. Presentations on spec-
ialty steels included discussion of high-strength low alloy steels, stain-
less steels, maraging steels, high speed steels and rapid solidification
processing as well as consideration of the roles of specific alloying
elements. An equally wide variety of topics was to be found in the hard
materials section with papers covering tungsten carbide-cobalt hard metals,
non-oxide ceramics, CVD processed hard materials and coatings, synthesis
of diamonds and sintered polycrystal1ine ultra-hard materials.
ν
vi Preface
These proceedings are divided into the following categories : plenary papers
covering the entire range of materials of interest in the conference, con-
tributed specialty steel papers and contributed hard materials papers.
Contributed papers were selected by the Programme Committee and refereed as
complete but draft manuscripts before the final versions were prepared.
It is hoped that this volume will provide timely reviews as well as
significant research and development contributions in the field of specialty
steels and hard materials.
Ν.R.Comins
J.B.Clark
Pretoria,
South Africa.
Acknowledgements
The sponsorship of the following organisations is gratefully acknowledged:
Boart International Limited
Council for Mineral Technology (MINTEK)
Council for Scientific and Industrial Research (CSIR)
Co-operative Scientific Programmes (CSPj
National Physical Research Laboratory (NRPL)
De Beers Industrial Diamond Division (Pty) Ltd (DEBID)
Highveld Steel and Vanadium Corp Ltd
ISCOR Ltd
Middelburg Steel and Alloys (Pty) Ltd
Nuclear Development Corporation of South Africa (Pty) Ltd
Sandvik (Pty) Ltd
SCAW Metals Ltd
Steel and Engineering Industries Federation of SA (SEIFSA)
South African Coal Oil and Gas Corp Ltd (SASOL)
Union Steel Corp of SA (USCO)
Appreciation is also due to:
Avis Rent-a-Car
South African Institute of Chemistry
South African Institute of Physics
South African Powder Metallurgy Association
South African Tourist Corp (SATOUR)
South African Transport Services
Technical Services Department, CSIR
The Southern Africa Stainless Steel Development Association (SASSDA)
and the following hosts for technical visits during the Conference:
Boart Hardmetals (Pty) Ltd
Chamber of Mines of South Africa
Council for Mineral Technology
De Beers Industrial Diamond Division (Pty) Ltd
Highveld Steel and Vanadium Corp Ltd
ISCOR Ltd
viii Acknowledgements
Union Steel Corp of SA
The Organizers also wish to thank those organizations which supported the
Conference by way of purchasing advertising or exhibition space or by send-
ing delegates.
Thanks are due particularly to the members of the various Conference Commit-
tees, and above all to the Organizing Committee and Conference Secretariat.
For Mrs Cilia Taylor, who ran the Secretariat and was responsible for the
conference arrangements and much of the co-ordination, a special vote of
thanks. The smooth running and friendly and stimulating atmosphere
achieved at this meeting is a tribute to the efforts of all these people.
Organizing Committee
Dr J Β Clark (Chairman) National Physical Research Laboratory, CSIR
Mr R Ρ Badenhorst ISCOR Ltd
Mrs Ν Basson National Physical Research Laboratory, CSIR
Dr J V Bee University of the Witwatersrand
Dr Ν R Comins National Physical Research Laboratory, CSIR
Mr Κ Dresselhaus Union Steel Corp of SA Ltd
Prof G G Garrett University of the Witwatersrand
Mr R A Pacey Co-operative Scientific Programmes, CSIR
Mr Β Ε Protheroe Chamber of Mines of SA
Dr G J Rees Boart International Ltd
Mrs Ρ M Taylor Symposium Secretariat, CSIR
Dr C R Thomas Middelburg Steel & Alloys (Pty) Ltd
Dr Ρ Τ Wedepohl Council for Mineral Technology
Dr R J Wedlake De Beers Industrial Diamond Division (Pty) Ltd
National Advisory Committee
Dr J Β Clark (Chairman) National Physical Research Laboratory, CSIR
Dr L Alberts Council for Minerai Technology
Dr Η Β Dyer De Beers Industrial Diamond Division (Pty) Ltd
Dr W Güldenpfennig Union Steel Corp of SA Ltd
Mr Hall Highveld Steel & Vanadium Corp Ltd
Mr C Hall Middelburg Steel & Alloys (Pty) Ltd
Dr Β Luyckx University of the Witwatersrand
Prof F R Ν Nabarro University of the Witwatersrand
Mr J M Pretorius Nuclear Development Corporation of South
Africa (Pty) Ltd
Mr Κ Prince ISCOR Ltd
Dr H J Smith Co-operative Scientific Programmes, CSIR
Dr A Strasheim National Physical Research Laboratory, CSIR
Prof G Τ van Rooyen University of Pretoria
Acknowledgements ix
International Advisory Committee
Dr F Ρ Bundy General Electric Company, USA
Prof M Cohen Massachusetts Institute of Technology, USA
Dr H Ε Exner Max-Planck-Institut für Metal 1forschung, FRG
Prof Dr H Fischmeister Max-Planck-Institut für Metallforschung, FRG
Prof R W Κ Honeycombe University of Cambridge, UK
Dr Β F Kieffer Teledyne Inc, USA
Prof F R Ν Nabarro University of the Witwatersrand, RSA
Dr M Semchyshen Climax Molybdenum Co, USA
Prof R Ε Small man University of Birmingham, UK
Prof Η Suzuki University of Tokyo, Japan
Prof G Thomas University of California, Berkeley, USA
Prof B-Z Weiss Technion, Israel
In preparing these proceedings, the editors have benefited from the untiring
help and support of many people. Mrs Sanny Biagio was responsible for the
administrative work on the proceedings, and Mrs Nicolene Basson for much of
the language editing of all manuscripts. Many papers required alterations
and this would not have been possible without the support of Mrs Susan Stephan,
Ms Maureen Taverner, Mrs Fran Obermeyer, Mrs Dottie Visser, Mrs Adele Foreman,
Mrs Santie Mörsner and Mrs Irma Uytenbogaardt, who during the Conference, and
after, assisted in the Editorial Office. Thanks also to Dr Martin Shaw, Mrs
Janet McQueer, Miss Dorothy Park and Mrs Margaret Comins for their assistance.
The authors are thanked for their co-operation throughout the refereeing
procedure, for their prompt submission of manuscripts, and where this was not
the case, their tolerance of the many telexes. Finally, to the many unnamed
referees who ensured that the manuscripts were up to standard, and all the
other people involved in making the Conference the success it was, our hearty
thanks.
Rapid Solidification Processing and the
Control of Structure/Property Relationships
M. Cohen
Massachusetts Institute of Technology, Cambridge, MA 02139, USA
ABSTRACT
In general, materials processing plays a major role in the structure/proper-
ty relationships which make materials useful to society. A recent illustra-
tion of this dynamic interplay is provided by rapid solidification process-
ing which leads to compositional uniformity and extremely fine dispersions
of second-phase precipitates. The fundamental modes of solidification are
discussed, particularly from the standpoints of solute partitioning at the
solid-liquid interface, solute trapping, and massive (segregationless)
solidification. Segraaationless solidification can produce unusually high
degrees of super-saturation relative to phases which are otherwise difficult
to dissolve in the solid matrix. This condition is favoured by supercooling
of the solidification process and by high velocity of the solid-liquid in-
terface. An important consequence of such rapid solidification is that the
alloy chemistry can be potentially designed to create small second-phase
precipitates which are particularly insoluble in the solid matrix and which
therefore resist coalescence on subsequent processing at high temperatures.
As a result, these dispersions are very effective in pinning grain bound-
aries and inhibitinq grain growth of the matrix phase. Some recent findings
are presented dealinq with the influence of these microstructural features
on structure/property relationships in alloy systems.
KEY WORDS
Rapid solidification; solidification morpholoqy; solute partitioning; in-
terfacial velocity; massive solidification; second-phase dispersions;
materials processinq/structure/property relationships.
INTRODUCTION
Structure/property relationships in materials constitute the essence of
materials science. Here, we try to discern the inner architecture of mate-
rials and then to connect this microdomain (throuqh theories, models, or
1
