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利用配位多面体生长基元理论研究了自生TiCp/Ti复合材料中TiC的生长习性.TiC晶体的配位多面体生长基元为TiC6.生长基元进入{100}面时为4个棱边同时联结,生长速率最快;不易显露;进入{111}面时为共面联结,生长速率最慢,容易显露.因此,TiC晶体的理想形态为以{111}面为显露面的八面体.TiC晶胚在熔体中生长时,受传热传质过程的影响,6个顶角所处的{100}方向生长速率加快,形态失稳;从{100}方向顶角部位生长出二次枝晶臂,最终形成棱面枝晶状TiC.如枝晶形成时低生长速度的晶面上形成大量的晶体缺陷,则它们的生长速度加快,棱面消失,成为光滑枝晶.
The growth habit of TiC in TiCp / Ti composites was studied by using the theory of coordination polyhedron growth. The coordination polyhedron growth of TiC crystal was TiC6. When the growth element entered the {100} plane, four edges joined together , The fastest growth rate; not easy to reveal; into the {111} surface coplanar connection, the slowest growth rate, easy to reveal .Therefore, the ideal form of TiC crystal {111} surface is exposed octahedron. When the embryo is grown in the melt, the growth rate of the {100} direction at the six vertices is accelerated and the morphology is not stable due to the heat and mass transfer process. The secondary dendrite grows from the top corner of the {100} direction Arm, eventually forming a dendrite dendritic TiC.If a large number of crystal defects are formed on the low growth rate dendrite crystal plane, their growth speed, facets disappear, become smooth dendrite.