摘要
Abstract
BACKGROUND:There are numerous studies about mechanical changes of recast cobalt-chromium ceramic al oys. However, little is reported on the mechanical properties of cobalt-chromium ceramic al oys containing once-used al oys after recasts. <br> OBJECTIVE:To study the effects of different proportion of once-used al oys to recasting cobalt-chromium al oys on their mechanical properties, including tensile strength, yield strength, elongation and hardness. <br> METHODS:Cobalt-chromium al oys cast samples were prepared and recast for three times (40%once-used al oys were added per time). The tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness of each specimen were measured. In addition, microscopic metal ographic observation was done. <br> RESULTS AND CONCLUSION:Being recast for three times, cobalt-chromiun al oys showed no significant differences on their tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness. GenerationⅠal oy samples had uniform size, smal diameter and smal carbide size distributing along the grain boundary, mainly exhibiting spherical and irregular wormlike forms. Generations Ⅱ and Ⅲ samples were uniform in shape, but crystal grains were coarsened a little. Carbide from Generation IV samples began to be coarsened, irregular wormlike carbides were increased in amount, and a few of non-metal ic inclusions could be found in grains. Cobalt-chromium al oys can be recast after addition of 40%once-used al oys for three times at least in air environment, without decrease of the mechanical properties.关键词
生物材料/组织工程口腔材料/钴铬烤瓷合金/不同比例/反复熔铸/机械性能/显微金相观察Key words
biocompatible materials/metal ceramic alloys/tensile strength/hardness tests分类
医药卫生
