Fabrication, Microstructure and Properties of In Situ Metallic Glass Matrix Composites

Fabrication, Microstructure and Properties of In Situ Metallic Glass Matrix Composites PowerPoint PPT Presentation


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Acknowledgments. Todd Hufnagel - Department of Materials Science, JHUAkihisa Inoue - IMR, Tohoku University, JapanLaszlo Kecskes - Army Research LaboratoryHaito Zhang - Department of Mech. Engineering, JHUJean-Francois Molinari - Department of Mech. Engineering, JHUMark Koontz - Department of Materials Science, JHUJing Li -Department of Materials Science, GITFunding Japan Science

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Fabrication, Microstructure and Properties of In Situ Metallic Glass Matrix Composites

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1. Fabrication, Microstructure and Properties of In Situ Metallic Glass Matrix Composites Cang Fan Department of Materials Science and Engineering Johns Hopkins University

2. Acknowledgments Todd Hufnagel - Department of Materials Science, JHU Akihisa Inoue - IMR, Tohoku University, Japan Laszlo Kecskes - Army Research Laboratory Haito Zhang - Department of Mech. Engineering, JHU Jean-Francois Molinari - Department of Mech. Engineering, JHU Mark Koontz - Department of Materials Science, JHU Jing Li -Department of Materials Science, GIT Funding Japan Science & Technology Corporation U.S. Department of Energy

3. It shows unique properties when grain size down to nano scale, even amorphous configuration.

4. Motivations Keeping, even improving the unique advanced properties of metallic glasses. High Strength (~2GPa); Large Elastic Limit (~2%) and Good Bending Ductility (in ribbon shape). Preparing samples in bulk size, controlling structure in micro even nano size => to develop advanced materials, to solve the problems. less even zero plasticity losing strength, becoming very brittle with crystallized or precipitated crystalline phases.

5. Outline Fabrication, Microstructure and Properties materials with in Situ nanoparticles dispersed in a metallic glass matrix. (In Situ Nano-size Particles / Metallic Glass Matrix Composites) materials with in Situ ductile particles in micro scale dispersed in a metallic glass matrix. (In Situ Micro-size Ductile Crystals / Metallic Glass Matrix Composites)

6. Experimental

7. Fabrication, Microstructure and Properties materials with in Situ nanoparticles dispersed in a metallic glass matrix (In Situ Nano-size Particles / Metallic Glass Matrix Composites) materials with in Situ ductile particles in micro scale dispersed in a metallic glass matrix (In Situ Micro-size Ductile Crystals / Metallic Glass Matrix Composites)

8. Nanocrystalline composites: 1990’s Al, Mg based alloys => higher hardness, higher strength.

9. TEM

10. Mixing Enthalpy and Atomic Size for Zr-TM-Al

11. DSC Covers (Differential scanning calorimetry)

13. To avoid nano crystals induced by ion milling thinning process, electrolytic polishing was used.

14. High-Resolution Electron Microscopy

15. Zr60Cu30-xPdxAl10 x = 10;

18. SEM

19. Summary Zr60Cu20Pd10Al10 : ?Tx = 62 K, Tg/Tm = 0.60 Bulk Nanocrystal/Amorphous Alloys were prepared in size of 4 mm diameter, 70 mm long. The existence of nanocrystals being only a few nanometers in diameter dispersed in an amorphous matrix was found to lead to an increase of both the strength and the ductility with increasing Vf of nanocrystals.

20. Fabrication, Microstructure and Properties materials with nanoparticles dispersed in a metallic glass matrix. (In Situ Nano-size Particles / Metallic Glass Matrix Composites) materials with in Situ ductile particles in micro scale dispersed in a metallic glass matrix. (In Situ Micro-size Ductile Crystals / Metallic Glass Matrix Composites)

22. Plasticity can be increased by adding micro-size crystalline second phase. Metallic glass infiltrated around fibers (e.g. W) Crystalline particles added to melt (e.g. Ta, Mo) Not In Situ forming, weak interface bond between particles and matrix.

23. Phase Diagram

25. Thermal Properties

26. Crystallization for x = 8

27. As Cast Rods XRD Patterns

28. As cast microstructure for x = 8 Composite

29. Distribution of Ta in Alloy

30. Structural Development

31. Mechanical Properties

32. Reasons for Enhanced Plasticity

33. Shear Band/Particle Interactions Shear bands shear particles to propagate. Ductile particles Impede shear band motion. Dislocation are created in particles when sheared.

35. Stress-strain covers and strain-strain covers

37. (A) The changes of voltage during compression. (B) The variances of the cross section calculated by (A). (C) The variances of the cross section calculated through true stress-strain curve.

39. Summary By using previously prepared metastable Zr-Ta super saturated solid solution binary ingots, successfully prepared a composite material consisting of precipitated micron-scale Ta-rich solid solution particles distributed in a bulk metallic glass matrix. The resulting material not only shows high strength (~2.1GPa), but also has dramatically enhanced plastic strain to failure in uniaxial compression relative to single-phase bulk metallic glasses. Finding strain-softening -- the macro scale character of shear bands behaviour through investigation of in-situ measurement. Combining the ductility of metal or alloys and the high strength of metallic glass.

40. Summary Motivations Preparing samples in bulk size, controlling structure in micro even nano size => to develop advanced materials. Solving the problems less even zero plasticity losing strength, getting very brittle with crystallized or precipitated crystalline phases.

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