Содержание
- 2. Acknowledgements Prof. GuoLiang Chen; Prof. Hywel A Davies; Prof. Peter K Liaw; Prof. George Smith; Prof.
- 3. Outlines I. Background & Motivations II. Results & Discussions III. Summaries
- 4. (1) Conventional alloys I. Background & Motivations Steel, A=Fe, B=Carbon, δB Cast Iron, A=Fe, B=Carbon, δB
- 5. (2) High Entropy Alloys HEAs=A+B+C+D+E; 50% 15% AlCoCrFeNi=HEA , Zhou, APL, 2007 CoCrCuFeNi=HEA, Yeh, MMTA, 2004;
- 6. Solid solution has higher entropy than the mechanical mixture does. 1.2 Thermodynamically For the regular solution:
- 7. Gibbs Free Energy ΔGmix =ΔHmix-TΔSmix
- 8. 1.3 Properties and Applications High Strength; Zhou, APL, 2007; High wear resistance; Lin, Surface Coating technology,
- 9. 1 Coatings, Barriers, etc. Diffusion barriers for Cu interconnections; Tsai, APL, 2008 2 Structural Materials 3
- 10. To understand what is the dominant factors for the phase formation of the HEAs 1 Atomic
- 11. 2 Enthalpy of Mixing; 3 Entropy of Mixing
- 12. 4 Cooling Rate 5 Tensile and compressive properties Critical cooling rate? Like the BMG? Tensile elongation=0?
- 13. CoCrFeNiCu1-yAly FCC BCC, High APE to Lower APE, with larger atoms Al 2.1. Alloying with different
- 14. Cu=1.278A CoCrFeNiAlCuy ( y=0, 0.25, 0.5) Ti0.5CoCrFeNiAlCuy No PHASE TRANSITION
- 15. Co=1.251A The smaller BCC transit to FCC firstly after adding Co Biger BCC1phase:2.913A; Smaller BCC2phase:2.872A
- 16. [Al1Co1Cr1Fe1Ni1]Tix alloys BCC+Ti BCC+BCC Ti=1.448A
- 17. After adding Ti, Laves phase forms
- 18. Zhou, APL, 2008 The transition is mainly lattice distortion induced and APE related
- 19. A schematic showing the additional effects
- 20. Zhang, AEM, 2008 2.2. Considering of the enthalpy of mixing ΔHmix Mg based BMG Zr based
- 21. 2.3. Considering of the entropy of mixing ΔSmix High Entropy is not good for the formation
- 22. 2.4 Cooling Rate AlCoCrFeNi
- 23. AlCoCrFeNi 2mm 5mm 8mm 10mm
- 24. AlCoCrFeNi
- 25. 2.5 Tensile and Compressive properties XRD pattern for the CoCrCuFeNiAl0.5 alloy.
- 26. Table Room temperature mechanical test results for the CoCrCuFeNiAl0.5 alloy εP: plastic strain; ε0.2 : yield
- 27. III. Summaries 1 Atomic size mismatch is the dominant factor for the phase formation of the
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