PART 4 基于扩散偶技术的组合测量方法 相图计算与扩散动力学模拟及其应用实例教学课件.pptVIP

U720/R95; 1000 h at 1150 °C Thermal Conductivity: Point defect possibility Laves Thermal Conductivity Mapping: Potential to evaluate mixing entropy?? Electrical conductivity measurement (in progress) Evanescent Microwave Probe Microscope (EMP): Can map electrical conductivity at very high resolution Require very flat porosity-free sample - Not easy for diffusion multiples Oak Ridge National Lab: Current pulse and decay curves Mapping electrical conductivity of phases simultaneously ORNL user facility application in process Electrical conductivity screening is critical for many materials: superconductors, semiconductors, thermoelectric materials, SOFC materials Micro-ray diffraction Lattice Parameter variation with composition: Oak Ridge National Lab (Gene E. Ice et al.): X-ray micro-diffraction at micron resolution Measurement of lattice parameter as a function of composition phases Thermal expansion coefficients Density calculations 200 mm Ti Nb Si NbSi2 Nb5Si3 Ti5Si4 Ti5Si3 Ti3Si Nb5Si3 Thermoelectric properties Science, Feb. 6, 2004 Magnetic Properties: Iso-Curie temperature composition Xu, Hartmann, Zhao Mo Co Cr Magnetic Properties: Magnetic moment 10-14 0 10 20 30 40 50 at.% Al Diffusion coefficient, m2/s 10-13 10-12 10-11 Ni NiAl 1204°C g g ’ b 600 800 1000 1200 1400 1600 1800 0 10 20 30 40 50 Ni NiAl at. % Al Liquid g (f.c.c.) b (B2) g ’ (L12) Temperature, oC Ni5Al3 0 1 2 3 4 5 0 400 800 1200 1600 2000 Distance, mm 0 20 40 60 80 100 Composition, at. % g g ’ b Ni Al Ni NiAl Ni NiAl 0 1 2 3 4 5 Serendipitous Observation: Point defect formation Point-defect formation Make serendipitous observations regular occurrences! Serendipitous Observation: Point-defect formation in Cr 500 mm NiAl Superalloy Diffusion Barrier Candidate diffusion barrier composition Superalloy NiAl Al 4 3 1 2 Applications of Diffusion multiples in Coating Development Diffusion Barriers Coatings Zhao, Jackson, Darolia Without diffusion barrier 75mm SRZ MX4 MX4 Coating MX4 Substra