Engineered Interfaces in Fiber Reinforced Composites Part 1 doc

ENGINEERED INTERFACES IN FIBER REINFORCED COMPOSITES JANG-KYO KIM & YIU-WING MA1 c f t ENGINEERED INTERFACES IN FIBER REINFORCED COMPOSITES ENGINEERED INTERFACES IN FIBER REINFORCED COMPOSITES Jang-Kyo Kim Department of Mechanical Engineering Hong Kong University of Science and Technology Clear Water Bay, Hong Kong Yiu-Wing Mai Centre for Advanced Materials Technology and Department of Mechanical & Mechatronic Engineering University of Sydney, NSW 2006, Australia 1998 ELSEVIER Amsterdam Lausanne * New York * Oxford - Shannon * Singapore Tokyo ELSEVIER SCIENCE Ltd The Boulevard, Langford Lane Kidlington, Oxford OX5 IGB, U.K. Library of Congress Cataloging-in-Publica~on Data Kim, Jang-Kyo. Engineered interfaces in fiber reinforced composites / Jang-Kyo Kim and Yiu-Wing, Mai. 1st ed. p. cm. Includes index. ISBN 0-08-042695-6 (hardcover) 1. Fibrous composites. I. Mai, Y. W., 1946- . 11. Title. TA418.9.C6K55 1998 620,1'18 DC21 97- 5 2002 CIP First edition 1998 ISBN 0-08-042695-6 0 1998 Elsevier Science 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. Q The paper used in this publication meets the requirements of ANSUNIS0 239.48-1992 (Permanence of Paper). Printed in The Netherlands It is a pleasure to write the foreword to this book. This work emphasizes for the first time in one volume how interfaces in fibrous composites can be defined, measured, improved and optimized. Many practitioners of composites technology will find in this book the information they have been seeking to match fiber and matrix at the interface, thereby obtaining the best mix of properties in the final application. Composites engineering is a relatively young field in which the test methods and measurement techniques are not yet fully developed. Even more important, the ideas linking the properties of composites to the interface structure are still emerging. This book not only reviews the historic and pragmatic methods for studying composites; but it also presents the most recent theories and fundamental tests of interface properties. This allows the reader to find the true framework of theory to fit his/her observations. The fact that two brittle materials can be brought together to give a tough product is the proof that interfaces are critical to composite properties. However, the complexities of this process depend on the raw materials, on the surface chemistry of the components, on the fabrication procedures, on the chemistry of hardening, and on the damage and corrosion sustained in use. A wide view of material science, chemistry, mechanics, process engineering and applications experience is necessary to focus successfully on the role of the interface. The authors have demonstrated such a global view in this volume. I have known Professor Mai for over 20 years. He is a foremost authority on fracture mechanics of composite materials, having studied polymer composites, cement, ceramic and natural composite systems, in the US, Britain, Australia and Hong Kong. In particular, he has made memorable contributions to the understanding of cracks and to the crack-inhibiting effects seen in fibrous composites. He has previously coauthored two books on fracture. Professor Kim originally worked in the composites industry and has returned during the past 10 years to study interface mechanisms more closely. He is currently working in the Hong Kong University of Science & Technology. In summary, the topic of engineered interfaces in composites is an important one, critical to the advance of the composites industry. Many practitioners from a range of disciplines are seeking the information which can be found in this book. The authors display the wide experience and theoretical knowledge necessary to provide a critical view of the subject. I strongly recommend this volume to the composite expert and student alike. Kevin Kendall Keele University, UK May 1997 V PREFACE The study and application of composite materials are a truly interdisciplinary endeavor that has been enriched by contributions from chemistry, physics, materials scicncc, mcchanics and manufacturing cnginecring. The undcrstanding of thc interface (or interphase) in composites is the central point of this interdisciplinary effort. From the early development of composite materials of various nature, the optimization of the interface has been of major importance. While there are many reference books available on composite materials, few of them deal specifically with the science and mechanics of the interface of fiber reinforced composites. Further, many recent advances devoted solely to research in composite interfaces are scattered in different published literature and have yet to be assembled in a readily accessible form. To this end this book is an attempt to bring together recent developments in the field, both from the materials science and mechanics perspective, in a single convenient volume. The central theme of this book is tailoring the interface properties to optimize the mechanical performance and structural integrity of composites with enhanced strength/stiffness and fracture toughness (or specific fracture resistance). It deals mainly with interfaces in advanced composites made from high performance fibers, such as glass, carbon, aramid, ultrahigh modulus polyethylene and some inorganic (e.g. B/W, A1203, Sic) fibers, and matrix materials encompassing polymers, metals/ alloys and ceramics. The book is intended to provide a comprehensive treatment of composite interfaces in such a way that it should be of interest to materials scientists, technologists and practising engineers, as well as graduate students and their supervisors in advanced composites. We hope that this book will also serve as a valuable source of reference to all those involved in the design and research of composite interfaces. The book contains eight chapters of discussions on microstructure-property relationships with underlying fundamental mechanics principles. In Chapter 1, an introduction is given to the nature and definition of interfaces in fiber reinforced composites. Chapter 2 is devoted to the mechanisms of adhesion which are specific to each fiber-matrix system, and the physico-chemical characterization of the interface with regard to the origin of adhesion. The experimental techniques that have been developed to assess the fiber-matrix interface bond quality on a microscopic scale are presented in Chapter 3, along with the techniques of measuring interlaminar/intralaminar strengths and fracture toughness using bulk composite laminates. The applicability and limitations associated with loading geometry and interpretation of test data are compared. Chapter 4 presents comprehensive theoretical analyses based on shear-lag models of' the single fiber composite tests, with particular emphasis being placed on the interface debond vii [...]... between Fiber Pull-out and Fiber Push-out 15 4 Cyclic Loading in Fiber Pull-out and Fiber Push-out 15 6 Introduction 15 6 10 1 Contents 4.5.2 4.5.3 Chapter 5 5 .1 5.2 5.2 .1 5.2.2 5.3 5.3 .1 5.3.2 5.4 5.4 .1 5.4.2 5.5 5.5 .1 5.5.2 5.5.3 5.5.4 5.5.5 5.5.6 Chapter 6 6 .1 6 .1. 1 6 .1. 2 6 .1. 3 6 .1. 4 6 .1. 5 6 .1. 6 6 .1. 7 6.2 6.2 .1 6.2.2 6.2.3 6.2.4 6.3 6.3 .1 6.3.2 6.4 xi Relative Displacements and Degradation Function 15 7... of Interface Frictional Properties 16 1 References 16 4 Surface Treatments of Fibers and Effects on Composite Properties 17 1 Introduction 17 1 Glass Fibers and Silane Coupling Agents 17 2 Structure and Properties of Glass Fibers 17 2 Silane Treatments of Glass Fibers 17 4 Carbon Fibers 18 3 Structure and Properties of Carbon Fibers 18 3 Surface Treatments of Carbon Fibers 18 6 Polymeric Fibers 19 6 Aramid Fibers... following forming of a new compound(s), particularly in MMCs; (f) by mechanical interlocking After Hull (19 81) and Naslain (19 93) 8 Engineered interfaces in jber reinforced composites The surface energy of a solid (i.e reinforcement in composites) , ysv, must be greater than that of a liquid (Le matrix resin), yLv, for proper wetting to take place Table 2 .1 gives values of surface energies for some fibers... Teflon fiber 16 .09 4 48.8 42.2 42.0 42.3 5 5 40.7 41. 9 5 5 37.8 5 Fiber- reinforced polymer matrix composites UD carbon fiber- epoxy matrix UD carbon fiber- PEEK matrix UD carbon fiber- polyamide (PA) matrix UD Kevlar fiber- polyamide (PA) matrix Woven carbon fabric-polyetherimide (PEI)matrix Woven carbon fabric-polyimide (PI) matrix UD carbon fiber- polypbenylene sulphide (PPS) YLV i 1 1 1 1 1 1 1 1 1 1 1 1 1. .. 2.3 2.3 .1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.3.7 2.3.8 2.3.9 2.3 .10 2.3 .11 Chapter 3 3 .1 3.2 Characterization of Interface Properties 5 Introduction 5 Theories of Adhesion and Types of Bonding 5 Adsorption and Wetting 7 Interdiffusion 12 Electrostatic Attraction 13 Chemical Bonding 14 Reaction Bonding 14 Mechanical Bonding 16 Physico-chemical Characterization of Interfaces 1 7 Introduction 17 Infrared... Criterion 11 0 Fiber Pull-Out Test 12 5 Introduction 12 5 Solutions for Stress Distributions 12 8 Interface Debond Criterion and Partial Debond Stress 13 1 Instability of Debond Process 13 5 Characterization of Interface Properties 13 8 Multiple Fiber Composite Model 13 9 Two-way Debonding Phenomenon 14 7 Fiber Push-out 15 0 Solutions for Stress Distributions 15 0 Debond Criterion and Debond Stresses 15 2 Comparisons... with Interface Control 279 Introduction 279 Fiber Coating and Intermittent Bonding Concept - Experimental Studies 2 81 Intermittent Bonding Concept 282 Fiber Coating for Improved Energy Absorption Capability 285 Fiber Coating Techniques 293 Theoretical Studies of Interphase and Three Engineered Interphase Concepts 295 Theoretical Studies of Interphase 296 Engineered Interface Concepts with Fiber Coating... Fibers 19 6 Ultrahigh Modulus Polyethylene (UHMPE) Fibers 2 01 Inorganic Fibers 205 Introduction 205 Selection of Coating Materials and Coating Techniques 206 Carbon Fibers 210 Boron Fibers 214 Silicon Carbide (Sic) Fibers 216 Alumina (A1,OJ Fibers 223 References 228 Interface Mechanics and Fracture Toughness Theories 239 Interface-related Fracture Toughness Theories 239 Introduction 239 Fiber- Matrix Interface... also be involved All these mechanisms take place at the interface region either in isolation, or, most likely, in combination to produce the final bond Reviews on these major mechanisms can be found in many references including Scolar (19 74), Wake (19 78), Kinloch (19 80, 19 82), Hull (19 81) , Adamson (19 82) and Kinloch et al (19 92) for polymer matrix composites; Metcalfe (19 74) for metal matrix composites. .. strength as well as to enhance fiber- matrix compatibility and stability during processing or fabrication of the 6 Engineered interfaces i fiber reinforced composites n chemical bonding, reaction bonding, and exchange reaction bonding (Kim and Mai, 19 93), which are schematically shown in Fig 2 .1 and discussed in the following sections In addition to the major mechanisms, hydrogen bonding, van der Waals forces . ENGINEERED INTERFACES IN FIBER REINFORCED COMPOSITES JANG-KYO KIM & YIU-WING MA1 c f t ENGINEERED INTERFACES IN FIBER REINFORCED COMPOSITES ENGINEERED INTERFACES IN. Wetting 7 Interdiffusion 12 Electrostatic Attraction 13 Chemical Bonding 14 Reaction Bonding 14 Mechanical Bonding 16 Physico-chemical Characterization of Interfaces Introduction 17 Infrared. Debond Stresses Comparisons between Fiber Pull-out and Fiber Push-out Cyclic Loading in Fiber Pull-out and Fiber Push-out Introduction 15 6 10 1 13 1 15 2 15 4 15 6 xi Contents 4.5.2. Relative