서지주요정보
$NiAl/Ni_3Al$ 2상합금의 상변태 및 미세조직에 미치는 제3원소 첨가효과 = The effect of ternary elements on phase transformation and microstructure of $NiAl/Ni_3Al$ two-phase alloy
서명 / 저자 $NiAl/Ni_3Al$ 2상합금의 상변태 및 미세조직에 미치는 제3원소 첨가효과 = The effect of ternary elements on phase transformation and microstructure of $NiAl/Ni_3Al$ two-phase alloy / 송성훈.
저자명 송성훈 ; Song, Seong-Hun
발행사항 [대전 : 한국과학기술원, 2003].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8014007

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 03021

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

The purpose of this study is to perform a fundamental study on the design and the development of an advanced high temperature intermetallic alloy by investigating the relationships between the phase transformation and the microstructure of two phase $NiAl/Ni_3Al$ alloys. $NiAl/Ni_3Al$ two phase alloys. The γ ′-Ni_3Al (L1_2 structure)$ and β-NiAl (B2 structure) have excited a good deal of interest for their possibility of application. The γ ′-Ni_3Al$ alloy is attractive due to the anomalous temperature dependence of flow and enhancement of room temperature ductility by boron addition. However, the $Ni_3Al$ alloy has problems such as high density, poor oxidation resistance and low melting temperature. The beta-NiAl alloy has attractive properties such as low density, high melting temperature and good oxidation resistance. The microstructural features of $NiAl+Ni_3Al$ two-phase (Ni-34Al)-X (X=Ti, Si, Nb) alloys are divided into three branched: Lamellar, Mesh1 and Mesh2. The most important factor of classification of microstructural features is austenite transition temperature($A_s$) of Ni-Al-X alloys. The $A_s$ temperature is sharply lowered with increasing the amount of ternary elements such as Ti, Si and Nb. The formation of the microstructure of the Lamellar alloy is brought about by following successive phase transformation: β prime (L1_0)→Ni_5 Al_3 (Pt_5 Ga_3)→ β+γ'. β'-martensite is quickly transformed by a re-ordering reaction to the $Ni_5 Al_3$ phase at 450$^\circ$C after quenching from 1300$^\circ$C. It is found that two types of β+γ' structure depended on ternary elements of the Mesh1 alloy are formed. The $Ni_5 Al_3$ phase of Si added Mesh1 alloy slowly precipitates from β-NiAl. This result indicates that the formation of the $Ni_5Al_3$ phase from β-NiAl is ignored. However, the phase transformation of $β→Ni_5Al_3$ of Ti and Nb added Mesh1 alloy is quickly formed by re-ordering at 250$^\circ$C. This difference is the reason of division of two types of microstructural features. The formation of the microstructure of the Mesh2 alloy is brought about by only phase transformation : β→β +γ'. The martensite temperature of Mesh2 alloy is too low to transform to β' -martensite. The γ' phase precipitates from the β phase and Widmanstatten structure is formed as observed in other alloy systems.

서지기타정보

서지기타정보
청구기호 {MMS 03021
형태사항 viii, 83 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Seong-Hun Song
지도교수의 한글표기 : 위당문
지도교수의 영문표기 : Dang-Moon Wee
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 80-83
주제 상변태
미세조직
마르텐사이트
Ni-rich NiAl
2상합금
transformation
microstructure
martensite
Ni-rich NiAl
two-phase
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