Indentation Fracture: Strength and Toughness for Brittle Materials Design

A comprehensive reference with demonstrations of advanced indentation fracture techniques in practical applications to enable better design and more efficient manufacturing Indentation Fracture describes and illustrates advanced applications of indentation fracture in evaluating strength, toughness, and related properties of brittle materials. The book enables better design, manufacture, performance, and reliability of brittle materials as elements in structural components. Emphasizing the practical applications of indentation fracture techniques, especially those of indentation-strength, the book builds on a development of indentation fracture mechanics to demonstrate clear quantitative comparisons and rankings of material fracture behavior, including the behavior of toughened materials. The book includes several case studies linking indentation fracture analyses and measurements to other phenomena including fragmentation cracking, edge chipping and dicing damage, scratching and the Mohs scale, and semiconductor grinding damage. Each case study highlights a different aspect of controlled flaw fracture measurements. The book enables readers to increase the utilization of glasses, ceramics, semiconductors, and similar brittle materials in load-bearing applications by demonstrating experimental indentation techniques to better characterize fracture. A primary focus of the book is demonstration of controlled flaw indentation-strength measurements. Written by an independent scientist with significant research contributions to the field, Indentation Fracture explores a range of topics including: Brittle fracture fundamentals, discussing equilibrium fractures on uniform and localized loading leading to the Griffith and Roesler equations Indentation strength variation, covering the effects of contact angle, spherical and flat punch contacts, and contacts in stressed and layered components Toughened materials strength observations in alumina, silicon nitride, glass ceramics, ferroelastics, and zirconia Strengths of silicon devices determined by wafer backgrinding, covering linear flaws in silicon, including single and multiple scratches, as well as linear, general, controlled, and grinding flaws Indentation Fracture is an essential reference on the subject for engineers across disciplines, nanotechnologists, geophysicists, and environmental scientists, along with graduate students in materials science and related programs of study.

Table of Contents:
Preface xiii Abbreviations and Symbols xv 1 Brittle Fracture Fundamentals 1 1.1 Brittle Components and Materials 1 1.2 Transformations on Brittle Fracture 4 1.3 Equilibrium Fracture on Uniform Loading 7 1.4 Equilibrium Fracture on Localized Loading 13 1.5 Stress-Intensity Factor and Toughness 17 1.6 Nonequilibrium Fracture 20 1.7 Fracture by Spatially Varying Loading 26 1.8 Summary 31 2 Indentation Cracking Behavior 37 2.1 Sharp Indentation of Brittle Materials 37 2.2 Indenter Shape Effects 47 2.3 Material Effects 53 2.4 Initiation 57 2.5 Summary and Discussion 61 3 Indentation Strengths: Invariant Toughness Materials 67 3.1 Indentation Strength of Brittle Materials 67 3.2 Fracture Mechanics of Indentation Strength 70 3.4 Indentation Strength Observations 108 3.5 Summary and Discussion 131 4 Indentation Strengths: Toughened Materials 141 4.1 Introduction 141 4.2 Microstructural Toughening in Brittle Materials 142 4.3 Toughened Materials Strength Analyses 150 4.4 Toughened Materials Strength Observations 153 4.5 Summary and Discussion 180 5 Indentation Strengths: Toughness Estimation 187 5.1 Introduction 187 5.2 Methods 188 5.3 Results 192 5.4 Discussion 198 5.5 Conclusions 200 6 Indentation Strengths: Reactive Environments 203 6.1 Introduction 203 6.2 Reactive Strength and Lifetime Analyses 210 6.3 Reactive Strengths Observations 220 6.4 Summary and Discussion 233 7 Dynamic Fragmentation Patterns in Flexed Ceramic Disks 241 7.1 Introduction 241 7.2 Number of Fragments 243 7.3 Distribution of Fragment Sizes 248 7.4 Crack Branching Distances 251 7.5 Application Examples 254 7.6 Conclusions 257 8 Edge Chipping at Small Scales and Strengths of Diced Components 263 8.1 Introduction 263 8.2 Sharp Contact Cracking at Edges 265 8.3 Edge Chip Size Variation 270 8.4 Edge Chip Strength Variation 273 8.5 Summary 277 9 Scratches and Lateral Cracking at Linear Sharp Contacts 279 9.1 Introduction 279 9.2 Analysis 282 9.3 Results 288 9.4 Mohs Scale Minerals 293 9.5 Summary and Discussion 298 10 Strengths of Silicon Devices Determined by Wafer Backgrinding 303 10.1 Introduction 303 10.2 Linear Flaws in Si 306 10.3 Strength of Si 309 10.4 Grinding Controlled Strength Model 322 10.5 Summary 327 11 Strength and Toughness of Cordierite Glass-Ceramic Composites 331 11.1 Introduction 331 11.2 Experimental Methods 332 11.3 Analysis Methods 339 11.4 Results 341 11.5 Conclusions 345 12 Crack Propagation in Toughened Materials 351 12.1 Introduction 351 12.2 Indentation Crack Extension Analyses 353 12.3 Crack Propagation Observations 359 12.4 Summary 366 13 Summary and Future 369 13.1 Introduction 369 13.2 Materials Comparisons 370 13.3 Future Topics 375 References 379 Index 381

About the Author :
Robert F. Cook, PhD, is a former NIST Fellow at the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, USA, and an independent scientist. He was a 2008 recipient of a U.S. Department of Commerce Silver Medal for Scientific/Engineering Achievement and is the author of over 200 peer-reviewed publications, 16 patents, and the book Particle Strengths.