치과주조용 Au-Zn-Pt 합금의 열처리와 상변태
Heat Treatment and Phase Transformation of a Dental Casting Au-Zn-Pt Alloy
소속 상세정보
이희경/Hee Kyung Lee
정충보/백창준/이경희/김형일/久恒邦博/Choong Bo Jung/Chang Jun Baek/Kyung Hee Lee/Hyung Il Kim/Kunihiro Hisatsune
KMID : 0362220000270030223
Abstract
치과주조용 Au-Zn-Pt 합금(77.1at% Au-12.4at% Zn-9.3at% Pt-0.7at% Ru-0.5at% Ta)의 열처리와 상변태를 경도 시험, X선회절 실험, 주사전자현미경 관찰, 전자탐침 미소분석으로 연구하여, 다음과 같은 결과를 얻었다. 용체화처리된 시편을 350℃에서
등온시효처리하면,
면심입방구조를 갖는 Au-rich α1상, 면심입방구조 규칙상 Pt3Zn 상인 α2상과 면심입방구조를 갖는 Pt-rich α3상의 3상이 α1상, α3상과 면심정방구조 규칙상 PtZn상인 β 상의 3상으로
변태하였다.
경화는 α2상에서 β상으로의 변태에 의한 기지의 격자변형에 기인한 것으로 보인다. 과시효 연화는 α2상에서 β 상으로의 변태에 의한 α1상과 α3상으로 된 nodule 조직의 조대화를 기인하였다. 본 실험합금의
특징은
면심정방구조를 갖는 PtZn규칙상의 도입이었다.
The aim of this study is to examine the age-hardening behaviour in a dental casting gold alloy without silver and copper, which contains a relatively high percentage of zine and platinum. Heat treatment and the associated phase transformation of
a
dental casting Au-Zn-Pt alloy, 77.1at% AU-12.4at% Zn-9.3at% Pt-0.7at% Ru-0.5at% Ta, were studied by means of hardness testing, X-ray diffraction study, scanning electron microscopic observations and electron probe micro-analysis. The following
results
were obtained. By the isothermal ageing of the solution-treated specimen at 350℃, three phases of the Au-rich α1 phase with a face-centered cubic structure, the α 2 phase with an ordered face-centered cubic structure
based
on
Pt3Zn and the Pt-rich α3 phase with a face-centered cubic structure were transformed into three phases of the α1 phase, the α3 phase and the β phase with an ordered face-centered tetragonal
structure
based
on PtZn. Hardening seemed to be due to the lattice strains of the matrix resulting from the transformation of the α2 phase to the β phase. Overaging with softening was attributed to the coarsening of the nodular structure which was
composed
of the α1 phase and the α3 phase resulting from the transformation of the α2 phase to the β phase. This gold alloy used in the present study was characteriazed by an introduction of the PtZn ordered phase with
a
face-centered tetragonal structure.
키워드
Age-hardening; Gold alloy; Phase transformation; PtZn phase; Pt3Zn phase;
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