CAJ | 학술논문

针对 AZ31B 和 AZ91D 异种镁合金材料的激光焊接问题，通过光学显微镜、拉伸试验、显微硬度测试等手段分析研究AZ31B 和 AZ91D 异种镁合金 CO2激光焊接头组织性能。结果表明：在功率为1800 W，焊接速度为600 mm／min，保护气流量为15 L／min 时，可以获得成形良好的焊缝。对焊接接头微观组织进行分析发现，接头热影响区不明显，熔合线附近母材侧晶粒未发生明显长大，焊缝晶粒明显细化；通过 XRD 检测可知焊缝区主要由α-Mg 和β-Al12 Mg17这2相组成；通过 EDS 能谱分析得到焊缝区 Mg、Al 元素的质量分数介于2种母材之间；通过拉伸试验发现，断裂位置位于 AZ91D 母材上，焊接接头抗拉强度高于AZ91D 母材，扫描断口显示断裂方式为脆性断裂；焊缝硬度高于2种母材硬度。
침대 AZ31B 화 AZ91D 이충미합금재료적격광한접문제，통과광학현미경、랍신시험、현미경도측시등수단분석연구AZ31B 화 AZ91D 이충미합금 CO2격광한접두조직성능。결과표명：재공솔위1800 W，한접속도위600 mm／min，보호기류량위15 L／min 시，가이획득성형량호적한봉。대한접접두미관조직진행분석발현，접두열영향구불명현，용합선부근모재측정립미발생명현장대，한봉정립명현세화；통과 XRD 검측가지한봉구주요유α-Mg 화β-Al12 Mg17저2상조성；통과 EDS 능보분석득도한봉구 Mg、Al 원소적질량분수개우2충모재지간；통과랍신시험발현，단렬위치위우 AZ91D 모재상，한접접두항랍강도고우AZ91D 모재，소묘단구현시단렬방식위취성단렬；한봉경도고우2충모재경도。
Studies on the microstructure and properties of dissimilar magnesium AZ31B and AZ91D joints welded by CO2 laser using optical microscope,tensile test,microhardness test and etc are presented.The results show that a sound weld can be ob-tained with a laser power of 1 800 W,a welding speed of 600 mm/min and a flow rate of shielding gas of 15 L/min.Analysis of microstructure of welded joint shows that the heat affected zone is not apparent,the growth of the grains in base metal close to the fusion line are not obvious,and the grain size in weld is refined.X-ray diffraction shows that there areα-Mg andβ-Al12 Mg17 phases in the welded zone.EDS analysis shows that the element’s content of Mg,Al in the welded zone are between that of the base metal AZ91D and AZ31B.Tension results show that the fracture is mainly happened on AZ91D,which indicates that the tensile strength of joint is higher than the base metal AZ91D,and the dominant fracture mechanism is brittle fracture.The hard-ness of welded zone is higher than two base metals.