Characterization of Interfaces in Dental Alloys by HREM

本研究项目的最终目的是基于界面表征方法，根据合金晶体的微观结构特征，采用科学的设计原则来定制新型牙科合金。50at系列合金相变相的鉴定。%Au和50at。采用电阻率法、x射线衍射法、常规透射电镜法和高分辨电镜法结合选择性区域电子衍射技术对%Cu→Ag进行了研究。Ag的加入降低了AuCu-Ag赝二元体系中Ag- cu双节点线外成分区AuCu II和AuCu I有序的临界温度。在AuCu-1.5at中，当微孪晶片与微孪晶片的另一取向变异体接触时，在微孪晶片的尖端附近发现了由相律预测的f. c. c. alpha_0相的无序固溶体。%Ag和AuCu-3at。% Ag)合金。虽然在AuCu-3at中，微薄血小板尖端的邻近区域被弓形。%Ag合金，在AuCu-1.5at中，与其他变体的微薄血小板接触的微薄血小板尖端邻近区域从未观察到这种弧。% Ag)合金。对老化形成的核结构进行了分析，并将其描述为由HREM图像中的AuCu II相和alpha_0相组成的复合核。alpha_0 + AuCu II和AuCu II之间的边界也因Ag含量而向下倾斜至二法线K线。在Au-50at。%Cu化学计量成分合金，在630K左右，无序固溶体直接时效和淬火后回火时效的热处理方式不同，表明合金中出现了spinodal有序。在630K以上的温度下，有序是由成核和生长机制诱导的，而有序则是均匀地由旋轴有序机制产生的。少

The eventual purpose of the present research project is the tailoring of new dental alloys by scientific designing principle which is governed by microstructural features of the alloy crystals based on an interfacial characterization approach.Identification of phases formed by phase transformation in a series of alloys from 50at. %Au and 50at. %Cu to Ag was studied by means of electrical resistivity, X-ray diffraction, conventional transmission electron microscopy and high resolution electron microscopy combined with selected area electron diffraction technique. Addition of Ag to AuCu alloy reduced the critical temperatures of ordering of AuCu II and AuCu I at the composition region outside of the Ag-Cu binodal line in AuCu-Ag pseudobinary system. A disordered solid solution of f. c. c. alpha_0 phase which was predicted from the phase rule was found adjacent to a tip of microtwin- platelets when they were in contact with another orientation variants of the microtwin platelets as an ine … More vitable consequence of strain accommodation in AuCu-1.5at. %Ag and AuCu-3at. %Ag alloys. Although an adjacent region of a tip of microthin platelet by arcuation in AuCu-3at. %Ag alloy, such arcuation was never observed at the adjacent region of microthin platelet tip contacted with another variants of microthin platelets in AuCu-1.5at. %Ag alloy. A structural configuration of nucleous formed by ageing was analysed and depicted as a composite nucleous consisted of AuCu II and alpha_0 phases from HREM images. The boundary between alpha_0 + AuCu II and AuCu II also sloped downward for Ag content to the binormal K line. In Au-50at. %Cu stoichiometric composition alloy, the occurrence of spinodal ordering at around 630K was implied from difference in heat treatment mode between a direct ageing from disordered solid solution and tempered ageing after quenching. Ordering wasinduced by nucleation and growth mechanism at a temperature above 630K, while the ordering was originated homogeneously from the mechanism of spinodal ordering. Less