서지주요정보
20% Ni maraging 강의 기계적 성질과 석출현상에 대한 Nb 영향 = The effects of Nb on mechanical properties and precipitation behavior of 20% Ni maraging steel
서명 / 저자 20% Ni maraging 강의 기계적 성질과 석출현상에 대한 Nb 영향 = The effects of Nb on mechanical properties and precipitation behavior of 20% Ni maraging steel / 백경욱.
저자명 백경욱 ; Paik, Kyung-Wook
발행사항 [서울 : 한국과학기술원, 1981].
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소장정보

등록번호

4001270

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 8110

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초록정보

This work is concerned with determining the effects of Niobium on mechanical properties and precipitation behavior of 20% Ni maraging steel. Heats of 20% Ni maraging steel with and without Nb (0.5 w/o) were prepared by vacuum melting. The ingots were subjected to hot forging and rolling, followed by solution treatment and aging. Hardness, tensile properties, and impact energy of the Nb-free and the Nbcontaining alloy were measured under the solution treated and maraged conditions. Transmission electron Microscopy was employed to identify morphology and composition of precipitates. Under the solution treated condition, the yield strength of the Nb-containing alloy (138Ksi) was about 4% higher than that of the Nb-free alloy (133Ksi). The 4% increase was attributed to solid solution hardening by adding 0.5% Nb in the matrix (Fe-Ni-Ti-Al). Upon maraging heat treatment, the yield strength of both the Nb-free and the Nb-containing alloy increased by an amount of 78% over the solution treated condition. The large increase in strength resulted from precipitation hardening. The yield strength of the maraged Nb-free alloy was 237 Ksi, compared with 246 Ksi of the maraged Nb-containing alloy. The increase of 4% (9 Ksi) in the yield strength was obtained by adding 0.5 w/o Nb. However, the Charpy impact energy tested at room temperature decreased by the amount of 25% by the addition of 0.5% Nb. This result shows that the addition of 0.5% Nb in the 20% Ni maraging steel is not desirable in the view of having optimum combination of strength and fracture toughness. Transmission electron microscopic study revealed that precipitate phases formed in the Nb-free alloy were FCC $Ni_3$ (Ti.Al) r' and HCP $Ni_3$ Ti $\eta$ phase, while is the Nb-containing, rod shape of orthorhombic $Ni_3Nb$ existed in addition to the r' and $\eta$ phases.

서지기타정보

서지기타정보
청구기호 {MMS 8110
형태사항 iv, 60 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Kyung-Wook Paik
지도교수의 한글표기 : 김영길
지도교수의 영문표기 : Young-Gil Kim
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 55-60
주제 Metals --Mechanical properties.
Precipitation (Chemistry)
Maraging steel.
Transmission electron microscopy.
기계적 성질. --과학기술용어시소러스
석출 (금속) --과학기술용어시소러스
첨가물 효과. --과학기술용어시소러스
마르에이징강. --과학기술용어시소러스
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