利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE)...利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE),金刚石立方结构,该化合物相形成孪晶,其孪晶面{111},孪晶方向[112],认为化合物相是以孪晶为晶核从熔体中优先其他化合物相形成并生长.展开更多
Cubic boron nitride particles coated by titanium nitride (TiN/cBN) as well as diamond particles coated by titanium carbide (TiC/diamond) were prepared by Ti molten salt deposition followed by heat-treatment process. c...Cubic boron nitride particles coated by titanium nitride (TiN/cBN) as well as diamond particles coated by titanium carbide (TiC/diamond) were prepared by Ti molten salt deposition followed by heat-treatment process. cBN or diamond particles were mixed separately with Ti powders and molten salts (KCl, NaCl and K<sub>2</sub>TiF<sub>6</sub>). The mixture was heated at 900 °C under argon atmosphere. The produced particles were heat-treated under hydrogen at 1000 °C. The morphologies and chemical compositions of the produced particles were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and focused ion beam (FIB). The results show that the cBN and the diamond particles are coated by nano-sized Ti layers. By heat-treatment of the Ti/cBN and TiC/diamond coated particles under hydrogen atmosphere, the deposited Ti layers were interacted by the in-situ transformation reaction with the surfaces of cBN and diamond particles and converted to titanium compounds (TiN and TiC), respectively.展开更多
文摘利用TEM、XRD等分析手段研究快速凝固Al Ti La合金中的化合物相的结构,以及高温退火后的结构,分析化合物相的高温稳定性,并提出化合物相的孪晶形核理论.快速凝固Al-Ti-La合金形成细小、圆整、弥散的金属间化合物相,经分析为Al20Ti2(RE),金刚石立方结构,该化合物相形成孪晶,其孪晶面{111},孪晶方向[112],认为化合物相是以孪晶为晶核从熔体中优先其他化合物相形成并生长.
文摘Cubic boron nitride particles coated by titanium nitride (TiN/cBN) as well as diamond particles coated by titanium carbide (TiC/diamond) were prepared by Ti molten salt deposition followed by heat-treatment process. cBN or diamond particles were mixed separately with Ti powders and molten salts (KCl, NaCl and K<sub>2</sub>TiF<sub>6</sub>). The mixture was heated at 900 °C under argon atmosphere. The produced particles were heat-treated under hydrogen at 1000 °C. The morphologies and chemical compositions of the produced particles were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and focused ion beam (FIB). The results show that the cBN and the diamond particles are coated by nano-sized Ti layers. By heat-treatment of the Ti/cBN and TiC/diamond coated particles under hydrogen atmosphere, the deposited Ti layers were interacted by the in-situ transformation reaction with the surfaces of cBN and diamond particles and converted to titanium compounds (TiN and TiC), respectively.
