Advances in Ceramic Armor IX

Ceramic Engineering and Science Proceedings Volume 34, Issue 5 - Advances in Ceramic Armor IX 

A collection of 14 papers from The American Ceramic Society’s 37th International Conference on Advanced Ceramics and Composites, held in Daytona Beach, Florida, January 27-February 1, 2013.This issue includes papers presented in the Armor Ceramics Symposium on topics such as Manufacturing; High-Rate Real-Time Characterization; Microstructural Design; Nondestructive Characterization; and Phenomenology and Mechanics of Ceramics Subjected to Ballistic Impact.

• Language: English
• Publisher: Wiley
• Release date: Dec 2, 2013
• ISBN: 9781118807804

Book preview

Preface

I had the pleasure of being the lead organizer for the 11th Armor Ceramics Symposium in 2013 at the 37th International Conference on Advanced Ceramics and Composites. I am very grateful for the guidance and support that was provided by Jeff Swab, Lisa Franks, Andy Wereszczak, Jim McCauley, and the organizing committee in putting this symposium together. Consistent with the history of this symposium, we strived to create a program that would foster discussion and collaboration between researchers from around the world in academia, government, and industry on various scientific issues associated with the topic of armor ceramics.

The 2013 symposium consisted of approximately 80 invited, contributing, and poster presentations from the international scientific community in the areas of synthesis and processing, manufacturing, materials characterization, testing and evaluation, quasi-static and dynamic behavior, modeling, and application. In addition, because of their importance for the foreseeable future, this symposium also had special focused topic sessions on Transparent Ceramics and Glasses, Boron-Icosahedral Based Ceramics, and the Army Research Laboratory’s new program on Materials in Extreme Dynamic Environments. Based on feedback from attendees, the 2013 symposium was a success, and the manuscripts contained in these proceedings are from some of the presentations that comprised the 11th edition of the Armor Ceramics Symposium.

On behalf of Jeff Swab, Lisa Franks, and the organizing committee, I would like to thank all of the presenters, authors, session chairs, and manuscript reviewers for their efforts in making this symposium and the associated proceedings a success. I would also especially like to thank Andy Wereszczak, Mike Golt, Steve Kilczewski, Bob Pavlacka, Gene Shanholtz, Eric Warner, and Jared Wright for stepping up at the last minute to host and chair the symposium when we were unable to due to Sequestration. Last, but not least, I would like to recognize Marilyn Stoltz and Greg Geiger of The American Ceramic Society, for their support and tireless efforts without which the success of this symposium would not be possible.

JERRY C. LASALVIA

Symposium Chair, Armor Ceramics

Introduction

This issue of the Ceramic Engineering and Science Proceedings (CESP) is one of nine issues that has been published based on manuscripts submitted and approved for the proceedings of the 37th International Conference on Advanced Ceramics and Composites (ICACC), held January 27—February 1, 2013 in Daytona Beach, Florida. ICACC is the most prominent international meeting in the area of advanced structural, functional, and nanoscopic ceramics, composites, and other emerging ceramic materials and technologies. This prestigious conference has been organized by The American Ceramic Society’s (ACerS) Engineering Ceramics Division (ECD) since 1977.

The 37th ICACC hosted more than 1,000 attendees from 40 countries and approximately 800 presentations. The topics ranged from ceramic nanomaterials to structural reliability of ceramic components which demonstrated the linkage between materials science developments at the atomic level and macro level structural applications. Papers addressed material, model, and component development and investigated the interrelations between the processing, properties, and microstructure of ceramic materials.

The conference was organized into the following 19 symposia and sessions:

The proceedings papers from this conference are published in the below nine issues of the 2013 CESP; Volume 34, Issues 2–10:

Mechanical Properties and Performance of Engineering Ceramics and Composites VIII, CESP Volume 34, Issue 2 (includes papers from Symposium 1)

Advanced Ceramic Coatings and Materials for Extreme Environments III, Volume 34, Issue 3 (includes papers from Symposia 2 and 11)

Advances in Solid Oxide Fuel Cells IX, CESP Volume 34, Issue 4 (includes papers from Symposium 3)

Advances in Ceramic Armor IX, CESP Volume 34, Issue 5 (includes papers from Symposium 4)

Advances in Bioceramics and Porous Ceramics VI, CESP Volume 34, Issue 6 (includes papers from Symposia 5 and 9)

Nanostructured Materials and Nanotechnology VII, CESP Volume 34, Issue 7 (includes papers from Symposium 7 and FS3)

Advanced Processing and Manufacturing Technologies for Structural and Multi functional Materials VII, CESP Volume 34, Issue 8 (includes papers from Symposium 8)

Ceramic Materials for Energy Applications III, CESP Volume 34, Issue 9 (includes papers from Symposia 6, 13, and FS4)

Developments in Strategic Materials and Computational Design IV, CESP Volume 34, Issue 10 (includes papers from Symposium 10 and 12 and from Focused Sessions 1 and 2)

The organization of the Daytona Beach meeting and the publication of these proceedings were possible thanks to the professional staff of ACerS and the tireless dedication of many ECD members. We would especially like to express our sincere thanks to the symposia organizers, session chairs, presenters and conference attendees, for their efforts and enthusiastic participation in the vibrant and cutting-edge conference.

ACerS and the ECD invite you to attend the 38th International Conference on Advanced Ceramics and Composites (http://www.ceramics.org/daytona2014) January 26–31, 2014 in Daytona Beach, Florida.

To purchase additional CESP issues as well as other ceramic publications, visit the ACerS-Wiley Publications home page at www.wiley.com/go/ceramics.

SOSHU KIRIHARA, Osaka University, Japan

SUJANTO WIDJAJA, Corning Incorporated, USA

Volume Editors

August 2013

RESPONSES OF SILICEOUS MATERIALS TO HIGH PRESSURE§

A. A. Wereszczak,¹ T. G. Morrissey,² M. K. Ferber,¹ K. P. Bortle,² E. A. Rodgers,² G. Tsoi,³ J. M. Montgomery,³ Y. Vohra,³ S. and Toller⁴

¹ Oak Ridge National Laboratory, Oak Ridge, TN 37831.

² ORISE Student Contractor, Oak Ridge National Laboratory, Oak Ridge, TN 37831.

³ University of Alabama - Birmingham, Birmingham, AL 35294.

⁴ LSP Technologies, Dublin, OH 43016.

ABSTRACT

Several silicate-based materials were subjected to high pressure loading using spherical indentation, diamond anvil cell (DAC) testing, and laser shock impact. The test methods were chosen because they can apply many gigapascal (GPa) of pressure, are relatively quick and inexpensive to experimentally conduct, produce repeatable results, induce a bulk material response, and enable in-situ or postmortem material analysis. Differences in apparent yield stress, hydrostatic pressure, and laser shock responses were observed among the materials and are described herein.

INTRODUCTION

The ballistic impact of transparent armor materials often involves the imposition of very high pressures. Transparent armor materials are almost always silicate (siliceous) based either in the form of glass or glass ceramics, and can exist in many forms and phases if crystalline.

The discussion and interpretation of high pressure response of siliceous based materials has continued for several decades now and arose from recognized pioneering work by Robert B. Sosman (regarding all things silica) and 1947 Nobel Prize recipient Percy W. Bridgman (high pressure testing). The reader is directed toward selected References [1–10] should interest exist in reviewing some of the more classical literature and useful reviews.

Relatively large densifications of glass under pressure are known to exist with initiations occurring as low as a few GPa and are known to be a strong function of the glass’s chemistry. Additionally, the presence of water in a glass is known to decrease its hardness [11], therefore its role in potential densification of a soda lime silicate glass is considerable too.

While pressure-induced densification is a sum of reversible and permanent densification, only recently has the latter started to be accounted for in ballistic modeling [12]. Ballistics testing can produce densification and enable densification’s study; however, it is expensive, time consuming, and not always amenable for postmortem material characterization. Consequently ballistic testing as a screening tool is impractical when there are many different potential glass candidates for transparent armor with different compositions. Therefore, three different high-pressure-application test methods were employed in this study to explore the high pressure response of siliceous materials. The methods were:

Spherical indentation testing with small indenter diameter. This test produces both high pressure and shear, along with loading and unloading histories which enable quantification of apparent yield stress and semi-quantification of energy absorption capability (hysteresis). The authors of the present report continue to assert this method is applicable for characterizing high pressure response, and continue to refine its testing protocol and interpretation to satisfy that.

Diamond anvil cell (DAC) testing. This test produces a hydrostatic stress, and when concurrently used with Raman Spectroscopy, enables the potential identification of changes of state of material as a function of quantified pressure for the various siliceous materials. Permanent densification is also detectable. Most high pressure studies involve this method.

Laser shock testing. This test produces high pressures but under dynamic conditions (impact event less than 30 ns) which enables the study of the effect of rate on high pressure. This is a non-standard test; however, the authors of the present report continue to consider its utility because it (1) applies high pressure under dynamic conditions, and (2) does so in the absence of a penetrating projectile thusly enabling the potential deconvolution of shock damage and contact damage.

There were two objectives with this work: investigate and compare the response of various siliceous materials to high pressures, and investigate the utility, advantages and disadvantages of these three test methods to impart that high pressure. This proceedings paper is a condensed version of a more comprehensive report published by the authors [13].

MATERIALS AND TEST METHODS

Several materials were evaluated but not all could be tested using all three test methods (spherical indentation, diamond anvil cell testing, and laser shock testing) owing to specimen size limitations in some cases. A summary of which materials were tested by each test method is listed in Table I. Among all those listed, the responses of four materials (fused silica, Starphire soda lime silicate glass, BOROFLOAT borosilicate glass, and ROBAX glass ceramic) were evaluated by all three test techniques. The air and tin sides of the three float glasses were also tested with all three test methods.

Table I. Material and Test Matrix.

The Hertzian contact stress field is well chronicled by Johnson [14] and a multitude of others, and is shown in Fig 1. The maximum pressure in the stress field is not located at the contact surface directly under the indenter; rather, it is located at a depth below the surface of approximately one-fourth the surface contact diameter. If yielding initiates, then it initiates at that location and not at the surface.

Figure 1. Spherical indentation stress field, image of tile being indented, and a schematic of the indenter depth of penetration sensor.

A Zwick microhardness indenter was used to perform spherical indentation as shown in Fig 1. This indenter independently measures compressive force and indenter depth of penetration during a programmed load-unload test waveform. A schematic of the indenter depth of penetration sensor is also shown in Fig 1. Its patented design avoids the sampling of machine compliance giving good fidelity of the measured response.

A displacement rate of 10 μm/min was used for the loading, and a diamond indenter diameter of 220 μm was used in the testing of the materials listed in Table I. An example of representative load-unload curves for an indentation test is shown in Fig 2. Acoustic emission sensing and analysis was used in all spherical indentation tests to discern where crack initiation occurred.

Figure 2. Example of a load-unload spherical indentation test data set and a screen shot of software used to determine the onset of apparent yielding using the generated indentation test data.

A computer program previously developed at ORNL was used to estimate the apparent yield stress. It compares the experimentally measured loading curve