INCREASEING THE TENSILE AND FATIGU STRENGTH MECHANISM OF DENTAL ALLOY

市售的12% Au-20% Pd-Ag-Cu合金已被标准化为12重量% Au和20重量% Pd，Ag和Cu的含量分别为45- 55重量%和15- 20重量%。通过将该合金中Cu的量增加到三元合金相图中所示的共晶组合物的极限，可以降低液相线。此外，共晶相的a1和a2相的结晶率变大，并且与a1固溶体相附近的成分相比，本文制备了一种实验合金，其中Cu的含量从12wt%的Au-Pd-Ag合金中增加到25wt%。研究了热处理工艺与该合金拉伸性能的关系。研究结果表明：1）在12wt%Au-20 wt %Pd-Ag-Cu合金中，通过在三元相图的共晶线上寻找Cu的加入量，可以使合金的时效区和固溶硬化区获得韧性;试验合金2）在905.6 ℃时，标准合金的液相线温度低于S-12的945.5 ℃和Castwell MC的915.9 ℃。添加Zn的合金的液相线温度为907.3 ℃。3）向本实验中使用的实验合金中添加2wt%的Zn引起脆化。然而，当这种合金在炉外进行空冷处理时，它的一些抗拉强度被牺牲，但它的韧性和伸长率增加。

Commercially available 12% Au-20% Pd-Ag-Cu alloys have been standardized at 12wt% Au and 20wt%Pd with the content of Ag and Cu varying from 45-55wt% and 15-20wt% respectively. By increasing the amount of Cu in this alloy to the limit of the eutectic composition shown in the ternary alloy phase diagram it is possible to lower the liquidus line. Moreone, the crystallization ratio of phase a1 and a2 of the eutectic phase becomes larger and, compared with the composition near the a1 solid-solution phase, a general enhancement of toughness can be anticipated.An experimental alloy was made for this study in which the amount of Cu in the commercial 12wt% Au-Pd-Ag alloy was increased to 25wt% and a study was made of the relationship between the heat treatment and the tensile characteristics of this experimental alloy. As a further study, 2wt% of Zn was added to this experimental alloy to see what effect shis might have on the mechanical properties.The re results of this study indicates :1) I am possible to give toughness to the aged area and solid-solution hardening area by seeking the amount if Cu in a 12wt%Au-20wt%Pd-Ag-Cu alloy on the eutectic line of a ternary phase diagram. The experimental alloy (standard alloy) had a improved elongation by from 15% to 22% compared with that of S-12 wrought material.2) At 905.6ﾟC,the liquidus phase temperature of standard alloy was lower than that of 945.5ﾟC for S-12 and 915.9ﾟC for Castwell MC.Also, the liquidus phase temperature for Zn added alloy was 907.3ﾟC.3) An addition of 2wt%Zn to the experimental alloy used in this experiment caused embrittlement. However, when this alloy is given air-cooled treatment outside the furnace, some of it's tensile strength is sacrificed but it's toughness increases and an elongation.