http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
개량 A7075-T73 합금의 고주기 피로 및 피로 균열 전파 거동
김관영 ( Gwan Yeong Kim ),김규식 ( Kyu Sik Kim ),박중철 ( Joong Cheol Park ),김세광 ( Shae K Kim ),윤영옥 ( Young Ok Yoon ),이기안 ( Kee Ahn Lee ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.4
The high cycle fatigue and fatigue crack propagation behaviors of the recently developed modified A7075-T73 alloy are investigated. This alloy is manufactured using Eco-Mg (including CaO) instead of a magnesium element. The alloy consists of an Al matrix, Al2CuMg, MgZn2, minute amounts of Ca phases and reduced Fe-based intermetallic or oxide. The modified A7075 alloy exhibits superior strengths (YS: 492 MPa, TS: 548 MPa) with a similar elongation (12.8%) compared with the conventional A7075. Furthermore, the high cycle fatigue properties are significantly improved (fatigue limit of 330 MPa at 107 cycles) compared with those of the conventional alloys. The fatigue crack propagation rate of the modified A7075 is similar or somewhat lower (higher resistance) than those of the conventional alloys. The superior tensile and fatigue properties of the modified A7075-T73 alloy are primarily attributed to the grain size refinement, evenly distributed strengthening phases (MgZn2 precipitates), and reduction of detrimental effects of the Fe- intermetallic phases and oxides.
김재우(Jae Woo Kim),조다희(Da Hee Cho),장광주(Gwang Ju Jang),박중철(Joong Cheul Park),이영철(Yeong Cheol Lee),구병춘(Byeong Choon Goo),조인식(In Sik Cho) 대한기계학회 2018 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.6 No.2
초음파 피로시험은 20㎑의 진동자를 이용한 가속피로시험기술로써 본 논문에서는 초음파피로시험선진기술의 동향을 분석하기 위하여 전문학술대회인 VHCF-6, 7(Very High Cycle Fatigue)에서 발표된 논문들을 위주로 새로운 아이디어의 장치 시스템 연구자료 소개와 각각의 기술적인 장점과 단점에 대하여 제시하고자 하였으며, 다양한 소재와 시편 형상들에 대한 방법으로 동탄성계수 측정관련 기술의 필요성을 설명하고자 하였다. 또한 국내에서 자체적으로 수행된 다양한 연구결과를 토대로 초음파 피로시험의 국내 신뢰성평가 기준 공고 소개와 추후 진행 중인, 응력비 변환과 저온 분위기등 다양한 조건과 요구에 대응할 수 있는 기반기술을 소개하고자 하였다. Ultrasonic fatigue test is an accelerated fatigue test technique using a 20㎑ oscillator. In this paper, in order to analyze the trend of the advanced technology of ultrasound fatigue tester (UFT), whose detailed information can be found in the conference papers published in VHCF-6 (2011), VHCF-7 (2014) (Very High Cycle Fatigue). dynamic young`s modulus, which can be obtained from acoustic test according to the ASTM E1875 standard. is required in order to obtain the maximum stress amplitude. The purpose of this paper is to present the research results of the UFT system and its technical advantages and disadvantages. Based on the experimental results of various studies performed at different stress ratio and cryogenic temperatures, the introduction of the reliability evaluation standard of the UFT system was presented.