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Study on the Mechanism of Enhanced Reactivity by Mechanical Alloying

机械合金化增强反应活性的机理研究

基本信息

批准号：
05452296
负责人：
NAGUMO Michihiko
金额：
$ 4.03万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

1.Reaction Systems : Reactivity at mechanical alloying has been related with the energy stored during milling for M (Zr, Ti, Nb, Ni, Al) -heptane and Ti-ceramics (Si_3N_4, SiC) systems. Correlation between the stored energy and the reacted quantity was revealed. Existence of the incubation period and threshold stored energy was observed.2.Reaction Process : The reaction products were examined by X-ray diffraction and DSC analyzes. For Ti-and Zr-heptane systems, at the early stage of reaction, the reaction phases are metastable that endure reversible change with temperature. The intermediate phases are likely the stacking faults stabilized by H and C atoms which are decomposition products of heptane. The lattice site of H atoms was investigated with thermal desorption spectroscopy and the difference between hcp Zr and bcc Nb was revealed.3.Sinterbility of the Milled Powders and Microstructures of the Sintered Materials : The particle size after milling was found to be refined about one order by the reaction resulting in improved sinterbility compared with conventional powders of ceramics or intermetallic compounds. Fine composites of TiAl-Ti_4Al_2C_2 and TiN-Ti silicides with the grain size of about 100nm were obtained.4.Mechanical Properties of the Sintered Materials : Tensile tests at elevated temperatures demonstrated elongation up to 400% at 1000C and 100% at 1500C for TiAl-Ti_4Al_2C_2 and TiN-Ti silicide composites, respectively. From the strain rate dependence of the flow stress, superplastic behaviors were confirmed.

1.反应体系：对M（Zr，Ti，Nb，Ni，Al）-正庚烷和Ti-陶瓷（Si_3N_4，SiC）体系的机械合金化反应性与球磨过程中的储能有关。揭示了储能与反应量之间的相关性。反应过程：用X射线衍射和DSC分析了反应产物。对于Ti-和Zr-庚烷体系，在反应初期，反应相为亚稳态，随温度可逆变化。中间相可能是由庚烷分解产物H和C原子稳定的堆垛层错。H原子的晶格位置进行了研究与热脱附光谱和hcp Zr和bcc Nb之间的差异被揭示。3.烧结粉末的烧结性和烧结材料的显微结构：球磨后的颗粒尺寸被发现细化约一个数量级的反应，从而改善烧结性与传统的陶瓷或金属间化合物粉末相比。4.烧结材料的力学性能：TiAl-Ti_4Al_2C_2和TiN-Ti硅化物复合材料在1000 ℃和1500 ℃的高温拉伸试验表明，其伸长率分别达到400%和100%。从流变应力的应变速率依赖性，超塑性行为被证实。