Advances in Ceramic Armor IX, Volume 34, Issue 5 E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: Ceramic Engineering and Science Proceedings
• Sprache: Englisch

Seitenzahl: 208

Veröffentlichungsjahr: 2013

Beschreibung

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.

Leseprobe

Contents

Cover

Half Title page

Title page

Copyright page

Preface

Introduction

Responses of Siliceous Materials to High Pressure

Abstract

Introduction

Materials and Test Methods

Results and Discussion

Summary

Acknowledgments

References

Edge-on Impact Investigation of Fracture Propagation in Boron Carbide

Abstract

Introduction

Edge-on Impact

Results with Pad B4C

Conclusions

Acknowledgment

References

Macroscopic Assessment of High Pressure Failure of B4C and B4C/SiC Composites

Abstract

Introduction

Test Procedures

Results and Discussion

Summary

Acknowledgement

References

Effect of Prestressing on the Ballistic Performance of Alumina Ceramics: Experiments and Modeling

Abstract

Introduction

Experimental

Experimental Results

Numerical Modeling

Conclusions

Acknowledgments

References

Geometrical Effect on Damage in Reaction Bonded Ceramic Composites Having Experienced High Strain Rate Impact

Abstract

Introduction

Experimental

Results & Discussion

Conclusion

Acknowledgement

References

Optimizing the Arrangement of Ceramic Tile Periodic Arrays for Armor Applications Using A Genetic Algorithm

Abstract

Scanner-Based Tile Dimensioning

Genetic Algorithm

Measurement Error Considerations

Conclusions

Acknowledgements

Works Cited

Al/Al2O3 MMCs and Macrocomposites for Armor Applications

Abstract

Introduction

Experimental Procedure

Properties of Al/Al2O3 MMCs

Design of a Macrocomposite System

Numerical Modeling of an Example Macrocompote System

Design and Fabrication of Macrocomposite Specimens

Summary and Conclusions

Acknowledgement

References

Mechanical Response Anisotropy in Hot-Pressed Silicon Carbide

Abstract

Introduction

Material and Experimental Description

Results and Discussion

Conclusions

Acknowledgements

References

Comparison of Armor Ceramics Made by Spark Plasma Sintering (SPS) and Pressureless Sintering

Abstract

Introduction

Experimental Procedure

Results and Discussion

Process Scale-Up

Mechanical Properties Characterization

Evaluation of Amorphization of SPS B4C

Summary and Conclusions

Acknowledgement

References

Pressureless Sintering of SiC-B4C Composites

Abstract

Introduction

Experimental

Results and Discussion

Conclusions

Acknowledgements

References

Development of Transparent Polycrystalline Beta-Silicon Carbide Ceramic Using Field Assisted Sintering Technology

Abstract

Background/Introduction

Experimental Method

Conclusion

References

Densification of Synthesized Boron Carbide Powders Using SPS

Abstract

Introduction

Experimental Procedure

Results

Summary

Acknowledgements

References

Consolidation of Aluminum Magnesium Boride (AlMgB14) by Pulsed Electric Current Sintering (PECS) Technique

Abstract

Introduction

Experimental

Results and Discussion

Conclusion

Acknowledgement

References

Ultrasonic Nondestructive Characterization of Transparent Spinel Microstructure

Abstract

Introduction

Experimental

Results and Discussion

Conclusion

Acknowledgements

References

Author Index

Advances in Ceramic Armor IX

Copyright © 2014 by The American Ceramic Society. All rights reserved.

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ISBN: 978-1-118-80749-1 ISSN: 0196-6219

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:

Symposium 1

Mechanical Behavior and Performance of Ceramics and Composites

Symposium 2

Advanced Ceramic Coatings for Structural, Environmental, and Functional Applications

Symposium 3

10th International Symposium on Solid Oxide Fuel Cells (SOFC): Materials, Science, and Technology

Symposium 4

Armor Ceramics

Symposium 5

Next Generation Bioceramics

Symposium 6

International Symposium on Ceramics for Electric Energy Generation, Storage, and Distribution

Symposium 7

7th International Symposium on Nanostructured Materials and Nanocomposites: Development and Applications

Symposium 8

7th International Symposium on Advanced Processing & Manufacturing Technologies for Structural & Multifunctional Materials and Systems (APMT)

Symposium 9

Porous Ceramics: Novel Developments and Applications

Symposium 10

Virtual Materials (Computational) Design and Ceramic Genome

Symposium 11

Next Generation Technologies for Innovative Surface Coatings

Symposium 12

Materials for Extreme Environments: Ultrahigh Temperature Ceramics (UHTCs) and Nanolaminated Ternary Carbides and Nitrides (MAX Phases)

Symposium 13

Advanced Ceramics and Composites for Sustainable Nuclear Energy and Fusion Energy

Focused Session

1 Geopolymers and Chemically Bonded Ceramics

Focused Session

2 Thermal Management Materials and Technologies

Focused Session

3 Nanomaterials for Sensing Applications

Focused Session

4 Advanced Ceramic Materials and Processing for Photonics and Energy

Special Session

Engineering Ceramics Summit of the Americas

Special Session

2nd Global Young Investigators Forum

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 with an idealized loading curve when the material is linearly elastic. Illustrations of its analysis are shown in Fig 2. The software identifies the load where the two curves diverge, and then this load is used in classical Hertzian theory to estimate the associated apparent yield stress.

The DAC produces a hydrostatic stress state on the test material (and the ruby). An illustration of that stress field is shown in Fig 3.

Figure 3. Images pertaining to DAC testing. Imposed hydrostatic stress (upper left), schematic of the DAC (upper right), wavelength shift for ruby as a function of pressure (lower left), and image of a test sample in the DAC (lower right).

The press consists of four main parts, a force generator, two diamond anvils, a gasket, and a pressure-transmitting medium. A schematic of the DAC, a photo of a piece of test material and ruby and gasket, and a peak-shift versus stress relationship are shown in Fig 3. The pressure in the diamond anvil cell can be remotely controlled using a gas-membrane loading mechanism.

Diamond anvil cell testing was performed on the materials listed in Table I. A 4:1 methanol-ethanol mixture was used for the liquid medium and its Raman spectrum was subtracted from the generated raw spectrum of each test. The Raman spectra were measured during compression to 20 GPa and on subsequent decompression to near ambient pressure.

During the laser shock process, the energy is applied very rapidly, with a rise time of approximately 4 ns, and then gradually decays over a couple tens of ns. The pressure application is nearly constant over a 5 mm diameter, and the “time zero” stress field is represented in Fig 4. The resulting pressure wave as a function of time is shown in Fig 4. Once this compressive wave (or P-wave) reaches the rear surface, it is reflected as a tensile wave propagating back towards the original impacted surface. During the initial stages of the reflection process, the net wave generated by the combination of the compressive and tensile waves is still primarily compressive in nature. During the mid-stage of the reflection a portion of the net wave is tensile while at the late-stage of the reflection it is predominantly tensile in nature.

Figure 4. Images pertaining to laser shock testing. Constant stress is applied (upper left), stress varies as a function of time (upper right), and picture and schematic of the setup (lower two images).

A high powered laser is used to focus a short duration energy pulse onto the surface of a test coupon as shown in Fig 4. A coating, typically black tape, is placed on the surface to facilitate the absorption of the laser beam energy. To direct the shock wave into the work surface, a transparent layer, usually flowing water, is continuously applied to the surface. During a specific pulse, the laser passes through the water and impacts the tape, and creates a plasma and a consequential compressive shock wave. The energy and pressure of that shock peens metals (i.e., the primary use of this laser shock concept); however, the authors in past work involving polycrystalline ceramics and the study of spallation [20], sought to explore its effect on siliceous (non-metallic) materials. The peak pressure is calculated from the energy-time curve.

RESULTS AND DISCUSSION

Spherical Indentation

A comparison of the estimated apparent yield stresses are shown in Fig 5. The BOROFLOAT’s apparent yield stress (~ 5.5 GPa) was about 25% lower than that of Starphire (~ 7.5 GPa and taken here to be a reference value). The apparent yield stress of the iron-containing soda lime silicate was equivalent, that of ROBAX was about 10% lower, and that of opal was about 80% lower than that of Starphire. Two different directions of loading were applied for alpha quartz testing due to anisotropy and the respective apparent yield stress values measured were about 15% lower than that of Starphire.

Figure 5. Comparison of apparent yield stress (left) and contrasted against literature values of HEL’s for three of the materials (right).

Diamond Anvil Cell

The Raman spectra for two of the eight tested materials are shown in Fig 6 as a function of pressure. The results for the other materials can be found in Ref. [13].

Figure 6. Raman spectrum as a function of pressure for the Starphire soda lime silicate glass (left) and BOROFLOAT borosilicate glass (right).

All the glasses showed evidence of permanent densification when they were hydrostatically pressured up to 20 GPa. Several of the changes were found to be reversible on decompression; however, quantitative determination of densification after the static pressure loading to 20 GPa were not made.

Peaks in the Raman spectrum tended to form for all the glasses and glass ceramics by the time a stress of 10 GPa was applied indicating long-range ordering was being induced while under pressure. The peak formations were reversible (i.e., absent after unloading). This suggests the material, while under pressure in a ballistic event, may have a different structure than it does under ambient temperature and pressure. Diffraction (X-Ray or neutron) analysis would need to be concurrently performed to explain what that long-range ordering was.

The amount of peak shifting per unit stress was much greater for the hydrated Starphire soda lime silicate glass than the baseline (unhydrated or as-received) Starphire. This indicates that introduced water into Starphire’s amorphous structure decreases stiffness.

It appears that an additional phase formed in pressurized Coesite sample at high pressures - perhaps Stishovite. This is evidenced by the appearance of new Raman peaks at pressures above 6.5 GPa. Diffraction analysis and repeat testing would confirm this.

Laser Shock

The minimum pressure needed to initiate damage (i.e., any observable cracking) in all the materials is shown in Fig 7. The fused silica exhibited the lowest damage initiation pressure (or peak pressure as described in the Materials and Test Methods Section).

Figure 7. Minimum laser shock pressure needed to initiate contact-side damage.

Damage initiated on the tin side at lower impact stresses than the air side for the float glasses (Starphire, BOROFLOAT, and the iron-containing soda lime silicate). Additionally, more failure initiation sites were visible on the tin side than the air side for an equivalent impact pressure. This is consistent with there being a greater size and concentration of surface-located flaws on the tin side than the air side. An artifact of the damage initiation starting at lower impact pressures on the tin side is that conical and secondary cracking spreads out at shallower depths than on the air side for an equivalent impact pressure.

The impact side damage, and its ease to initiate, is most likely limited by the surface-flaw population that exists on the glasses and glass ceramics. Surface flaws are a characteristic of the material’s handling history and are not necessarily characteristic of the material itself. A smaller flaw size should result in greater impact damage resistance. The trend of impact side damage initiation stress correlated (Fig 8) with previous work of the authors on spherical indentation ring crack initiation force [19–21]; this is consistent with impact side damage initiation being associated with surface-located flaws. Impact side damage initiation stress did not correlate with apparent yield stress as shown in Fig 8.

Figure 8. Minimum pressure to initiative shock damage increased with ring crack initiation force measured using spherical indentation in previous studies by the authors [19–21]. There was no correlation between onset of laser-shock-induced damage on the impact surface and apparent yield stress.

A representative example of the commonly observed impact side damage zone is shown in Fig 9