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基于电子束区域熔炼中熔区上力的平衡关系式,计算获得了基座法、等径区熔法两种工艺下稳定成形熔区高度的表达式,探讨了试样尺寸、晶体生长角和凝固速率等参数对六种贵金属稳定成形熔区高度的影响.结果发现,区熔相同尺寸试样时,六种贵金属能够稳定成形熔区高度大小依次排序为Ru>Pd>Ir>Pt>Ag>Au.同时获得了这六种贵金属的晶体生长角在8.4°—10.7°之间,而实际的晶体生长角与界面生长机制有关.在基座法中,连续生长机制所能支撑的熔区高度最小,而等径区熔法中连续生长机制支撑的熔区高度大于位错生长机制和小面生长机制.这三种晶体界面生长机制中连续生长方式对晶体生长角和区熔熔区高度影响较小,有利于贵金属区熔单晶制备.另外当凝固速率达到2.4 mm·min 1,位错和小面生长机制对区熔熔区高度的影响也变得很小,预测的工艺参数与Ir和Ru单晶区熔实验报道结果基本符合.
Based on the equilibrium relationship between the upper forces of the molten zone in the electron beam region smelting, the expressions of the height of the stable forming region under the two processes of the base method and the equal radius region melting method were calculated. The effects of the size of the sample, Coagulation rate and other parameters on the stability of the forming zone of the six precious metals were studied.The results show that the order of the heights of the stable forming zones of the six precious metals in order to melt the same size zone is Ru> Pd> Ir> Pt> Ag> Au. At the same time, the crystal growth angles of the six noble metals are between 8.4 ° -10.7 °, and the actual crystal growth angle is related to the interfacial growth mechanism. In the susceptor method, the height of the molten zone supported by the continuous growth mechanism And the height of the molten zone supported by the continuous growth mechanism in the equiaxed zone melting method is greater than that of the dislocation growth mechanism and the facet growth mechanism.The continuous growth mode of the three crystal growth mechanisms has a great influence on the crystal growth angle and the melting zone Smaller, which is beneficial to the preparation of molten metal in the zone of noble metal.In addition, when the solidification rate reaches 2.4 mm · min 1, the influence of dislocation and facet growth mechanism on the height of zone melting zone becomes very small. The predicted process parameters are similar to Ir And Ru single crystal zone melting Test results are consistent with reports.