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A Study for Low Carat Gold Alloys with Age-hardenability at Intraoral Temperature

口内温度时效硬化低克拉金合金的研究

基本信息

批准号：
11671940
负责人：
HISATSUNE Kunihiro
金额：
$ 1.28万
依托单位：
Nagasaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Gold alloys are one of the most useful materials in dental treatment. The required strength is an application of heat treatment wife age4iardening,The hardening is controlled by the formation of ordered phase with L1_0 structure. However, there appears one serious problem of the. deformation on prosthetics, because the L1_0 is different from the matrix phase (fcc) in crystal structure. The purpose of the present study is to clarify the possibility for use of L1_2 phase (fcc) having the same structure. As an L1_2 structure, Cu_3Au and CuAu_3 were selected. Four binary and six ternary alloys were prepared by vacuum-melting in a high-frequency induction furnace. After the solution treatment, two modes were employed, namely anisothermal and isothermal annealings. Th age-hardening behaviors were examined by electrical resistivity measurements, hardness tests, X-ray diffraction and transmission electron microscopy. The main results were as follows ;(1) It is difficult for only L1_2 phase to obtain appropriate strength for dental prosthetics. Partial introduction of the L1_0 phase (CuAu I) is demanded for the required strength.(2) Remarkable age-hardening was due to the formation of the CuAu I ordered phase in the Au_3Cu ordered matrix.(3) Three types of phase transformation in the grain interior from the disordered phase to the equilibrium phases (L1_0 + L1_2) were detected during the isothermal aging. The difference can be interpreted in terms of the free energy.

金合金是牙科治疗中最常用的材料之一。所要求的强度是时效后的热处理硬化，硬化是由L1_0组织的有序相的形成控制的。然而，出现了一个严重的问题。由于L1_0与基质相(Fcc)在晶体结构上不同，导致假体变形。本研究的目的是阐明具有相同结构的L1_2相(FCC)使用的可能性。作为L1_2结构，选择了Cu3AU和CuAu3。采用高频感应炉真空熔炼法制备了4种二元合金和6种三元合金。固溶处理后，采用了两种方式，即等温退火和非等温退火。通过电阻率测量、硬度测试、X-射线衍射仪和透射电子显微镜研究了合金的时效硬化行为。主要研究结果如下：(1)L1_2相难以获得合适的牙体修复强度。(2)由于在Au_3Cu有序基体中形成了CuAu_i有序相，导致了显著的时效硬化.(3)在等温时效过程中，晶内从无序相到平衡相(L10+L12)发生了三种类型的相变.这种差异可以用自由能来解释。