CAJ | 학술논문

利用金相显微镜、扫描电镜、X线衍射分析和维氏硬度测试仪等手段，研究热处理工艺对Y变质的Mg-7Al合金微观组织及硬度的影响。结果表明：T4工艺处理后β-Mgl7A112相几乎全部溶入α-Mg基体中，而高熔点的稀土化合物Al2Y相在试验温度下不能分解和固溶；T6工艺处理使β-Mgl7A112相以层片状和点状共存的方式再次析出，改善了其原本粗大的网状形貌，时效温度越高，β-Mgl7A112相的层片状析出量越少，且Y的加入会抑制和推迟β-Mg17A112相的析出；Mg-7Al-xY合金最佳热处理工艺为400℃×8 h+200℃×6 h，当Y的质量分数为0.5%时，合金的硬度由铸态的62.2HV升高到时效态的85.95HV，比铸态提高了23.75%。
이용금상현미경、소묘전경、X선연사분석화유씨경도측시의등수단，연구열처리공예대Y변질적Mg-7Al합금미관조직급경도적영향。결과표명：T4공예처리후β-Mgl7A112상궤호전부용입α-Mg기체중，이고용점적희토화합물Al2Y상재시험온도하불능분해화고용；T6공예처리사β-Mgl7A112상이층편상화점상공존적방식재차석출，개선료기원본조대적망상형모，시효온도월고，β-Mgl7A112상적층편상석출량월소，차Y적가입회억제화추지β-Mg17A112상적석출；Mg-7Al-xY합금최가열처리공예위400℃×8 h+200℃×6 h，당Y적질량분수위0.5%시，합금적경도유주태적62.2HV승고도시효태적85.95HV，비주태제고료23.75%。
Effects of heat treatment on microstructure and hardness of Mg-7Al-xY magnesium alloy were investigated by the means of optical microscopy,scanning electron microscope,X ray diffraction analysis and Vivtorinox hardness tester. The results show that the net-like β-Mgl7A112 distributed along grain boundary disappears completely after T4 heat treatment,while at the test temperature,Al2Y phase with high melting point can not be decomposed. Aging after solution treatment causes the β-Mg17Al12 phase to precipitate once more in the form of layered and spotted state,which improves its original pattern of thick mesh;and the higher temperature in aging treatment,the less amount of layered β-Mg17Al12 phase can be precipitated. The precipitation behavior of theβ-Mg17Al12 phase can be restrained and delayed due to the mixing of Y. The proper heat treatment parameters of the Mg-7Al-xY alloy is 400℃for 8 h and 200℃for 6 h,when the Y content in the alloys is 0.5%,the hardness is improved from 62.2HVto 85.95HV,23.75%higher than that of as-cast.