서지주요정보
W-250 maraging강에서 Ti 함량과 열처리가 기계적 성질, 미세조직 및 시효거동에 미치는 영향 = The effects of Ti and heat treatment on mechanical properties, microstructure, and aging behavior in W-250 maraging steels
서명 / 저자 W-250 maraging강에서 Ti 함량과 열처리가 기계적 성질, 미세조직 및 시효거동에 미치는 영향 = The effects of Ti and heat treatment on mechanical properties, microstructure, and aging behavior in W-250 maraging steels / 정재영.
저자명 정재영 ; Jung, Jae-Young
발행사항 [서울 : 한국과학기술원, 1988].
Online Access 원문보기 원문인쇄

소장정보

등록번호

4105098

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 8828

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

The effects of Ti-content (0.65-1.48 Ti) on tensile properties and impact toughness in Fe-18.5 Ni-4.5 W- Ti- 0.05 Al with varying heat treatments were investigated. Heat treatment temperatures varied from 750℃ to 950℃ for solution treatments and from 375℃ to 650℃ for aging treatments. The optimum condition of high yield strength (250 ksi) and good toughness was obtained in the alloy composition of Fe- 18.5 Ni- 4.5 W-1.35~1.4 Ti -0.05 Al after the solution treatment at 900℃ and aging at 500℃ for 3 hrs. It was found that impact energy and tensile properties were sensitivie to the Ti content, under a standard aging treatment (500℃/3hrs); the tensile strength increased from 1400 MPa to 1900 MPa and the impact energy decreased from 54 J to 12 J as the Ti content increased from 0.65 to 1.48 Ti. Overaging condition was designed to simulate the condition of HAZ during welding cycles. The retained austenite formed during the overaging treatment did not offer any advantage in impact energy compared with maraged state of the same level with fully martensite structure. As aging temperature increased from 550℃ to 650℃ with varying aging time, the amounts of retained austenite were studied by X-ray diffraction analysis. By varying aging temperatures from 375℃ to 550℃, the aging kinetics were studied by hardness measurements. At low temperature aging treatment, the exponent of Johnson - Mehl equation(n) was about 0.6. By the value of time to reach the maximum hardness, apparent activation energy estimated was about 295 KJ/mole. This value was about the same as the activation energy for volume diffusion of W in bcc-iron, 293KJ/mole reported. The precipitates formed during aging treatment were identified by transmission electron microscopy. The major strengthening precipitates formed during the aging treatment of Co-free W-bearing maraging steel was hexagonal n-$Ni_3Ti$ and orthorhombic $Ni_3W$. The orientation relationships of the precipitates and matrix were identified by electron diffraction spot pattern analysis. The orientation relationships of n-$Ni_3Ti$ was $(110)_α$//$(0001)_n$ and $<1\overline{1}1>_α$ // $[2\overline{1} \overline{1}0]_n$, while those of $Ni_3W$ was $(110)_α$// (010) and $<1\overline{1}1>_α$// [100]

서지기타정보

서지기타정보
청구기호 {MMS 8828
형태사항 [iii], 65 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Jae-Young Jung
지도교수의 한글표기 : 김영길
지도교수의 영문표기 : Young-Gil Kim
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 63-65
주제 Metals --Heat treatment.
Microstructure.
Aging.
Metals --Mechanical properties.
마르에이징강. --과학기술용어시소러스
열 처리. --과학기술용어시소러스
기계적 성질. --과학기술용어시소러스
미세 구조. --과학기술용어시소러스
시효. --과학기술용어시소러스
QR CODE qr code