Formation of Composite Layer Containing TiC Precipitates by Electrical Discharge Alloying
Formation of Composite Layer Containing TiC Precipitates by Electrical Discharge Alloying
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放电合金化含TiC析出复合层的形成
DOI：
10.2320/matertrans1989.38.630
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Eiji Kuribe
中科院分区：
文献类型：
--
作者：
Y. Tsunekawa;M. Okumiya;N. Mohri;Eiji Kuribe
为了改善铝基复合材料的摩擦磨损性能，采用一种新的方法--电火花合金化法对铝基复合材料进行表面改性。包含在绿色致密电极中的钛以及从工作流体分解的碳和硅通过单个放电电弧转移到衬底表面。差距电压的增加使差距距离变宽。由于放电电弧附近的工作流体的蒸发引起的压力随着间隙距离的增大而减小，所以如果差距电压高，则难以吹掉具有富集的钛和碳的放电弧坑的顶层。结果表明，随着间隙电压的增加，改性表面中TiC的体积分数增加，改性表面的硬度提高。放电合金化工艺不仅可以在几分钟内获得厚度近80 μm的TiC复合镀层，而且可以通过改变工艺参数之一的差距电压来获得不同体积分数的TiC。通过改变TiC的体积分数，可以控制改性表面的硬度具有7-14 GPa的任意值。还认识到，该方法提高了改性表面的耐磨性。
In order to improve friction and wear characteristics, surface modification of aluminum matrix composites was carried out by applying a new method named Electrical Discharge Alloying, in which a conventional electrical discharge machine can be utilized. Titanium contained in a green compact electrode, and also carbon and silicon decomposed from a working fluid are transferred to the substrate surface through a single discharged arc. An increase in the gap voltage widens the gap distance. Since the pressure due to the evaporation of working fluid in the vicinity of a discharged arc decreases with a gap distance widened, it is hard to blow off the top layer of discharged craters with enriched titanium and carbon if the gap voltage is high. Consequently, the volume fraction of TiC in the modified surface increases with increasing gap voltage, and then the hardness of modified surfaces becomes high. The process, electrical discharge alloying, makes it possible not only to coat a composite layer containing TiC precipitates with a thickness of nearly 80 μm within a few minutes, but also to get different volume fractions of TiC by changing the gap voltage, which is one of the process parameters. Hardness of the modified surface can be controlled to have any value of 7-14 GPa by varying the volume fraction of TiC. It is also recognized that the process improves wear resistance of the modified surfaces.