摘要:
通过对DT合金各相的成份、形貌、结构特点的观罕及热处理工艺对其影响的分析,揭示出该合金的显微特征,并就进一步提高合金性能从理论上进行了初步探讨。碳化钨相与基体相在加热到高温时发生相互溶解和扩散。各元素的分布有一定的规律。扩散的结果强化了两相的结合。碳化钨相存在溶解、析出和长大倾向不同的两种颗粒,它们的形貌和成份均不同,一种是W向基体扩散较多、外形已明显"球化"的颗粒;另一种是W向基体扩散较少,外形尚未明显"球化"的颗粒。通过比较认为:若能使合金中碳化钨相颗粒实现"球化,"可能有利于提高性能。固溶有其他元素的碳化钨相仍保持WC的结构类型,但晶格常数大于WC,而且随回火温度提高,晶格常数a和c减小。
Abstract:
The micro characteristics of DT alloy have been given by composition analysis, mophology and structural features of various phases and by the influence of heat treatment process, therefore, the improvement of its properties has been theoretically discussed. Mutual solution and diffution carry on between tungsten carbide phase and matrix phase when the alloy is heated at high temperature. The distribution of various elements is in accord with certain rules. The result of mutual diffusion is increase of binding strength between two phases. In there are two kinds of tungsten carbide particles with different tendency of solvation, deposition and growth. They have different mophology and composition. One kind of this particles has more W diffusion into matrix and obvious tendency to form spherical particles, while the other hind of particles has less W diffusion into matrix and unobtrusive tendency to form spherical particles.It is known by comparison between them that the properties of alloys can be improved if tungsten carbide particles become spherical. Tungsten carbide phase solubilized other elements remains the oiginal structurol but the lattice parameters are less than the original WC. and lattice parameters a and c will further decrease with the increase of tempering temperature.
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