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电弧增材制造技术基于分散累加原理,可实现镍基高温合金复杂结构快速无模加工,是一种广受关注的先进加工技术。该研究以高温耐蚀合金Inconel 617增材制造块体为研究对象,采用OM,SEM及万能拉伸试验机等手段分析了增材制造镍基合金块体微观组织及力学性能。研究结果表明,Mo元素在柱状枝晶间偏析,促使大尺寸的Laves相沿枝晶析出。在拉伸应力下,Laves相由于脆性较高,易发生断裂,诱发裂纹萌生。由于裂纹扩展路径在不同方向拉伸时存在显著差异,导致增材制造构件沿沉积方向强度(900 MPa)显著高于垂直沉积方向强度(700 MPa)。该研究为电弧增材制造镍基合金的组织性能调控奠定了一定基础,为进一步推动电弧增材制造镍基合金构件的应用进行了有益探索。 相似文献
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Agglomerated fluxes with different basicity index designed in laboratory were used to study electrochemical reactions between slag and metal in submerged arc welding under both power polarities. The droplet metal oxygen and nitrogen contents were measured using oxygen-nitrogen instrument in order to analyze indirectly metallurgy electrochemical reactions taking place in cathode and anode of welding arc. The results show that just in the period of droplet growth at the tip of consumable electrode the electrochemical oxygen contamination is produced in the case of direct current electrode positive polarity whereas electrochemical oxygen lost in electrode negative polarity. Furthermore, the results indicate that the basicity index of molten slag has great influence upon electrochemical reaction. With basicity index increasing, the effect of oxygen transferring resulted from electrochemistry becomes more evident for reacting dynamics depended on ion characteristics of molten slag. The effect of basicity index on metal-slag electrochemical reaction is contrary to traditional thermo-chemical reaction and therefore it is necessary to be considered as a metallurgy factor. 相似文献
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热塑挤压改善镁合金熔焊接头疲劳性能及其微观机制 总被引:1,自引:0,他引:1
以AZ31B镁合金为试验材料,用同质成分丝材作填充材料进行TIG对接焊.将获得的熔焊接头在真空热压炉中实施400℃恒温热塑挤压变形,然后再进行室温疲劳性能试验.对试验试样借助于扫描电镜、微观金相及能谱分析等手段探讨热塑挤压改善镁合金熔焊接头疲劳性能方法及其微观机制.结果表明,热塑挤压能够有效地提高镁合金熔焊接头疲劳寿命,其改善机制主要基于400℃恒温挤压变形有助于熔合区氧化物夹杂的破碎及微裂纹的密实、愈合,并促使熔合区粗大α晶粒形成亚晶界以细化组织;同时热塑挤压变形又使焊缝组织通过动态再结晶实现组织重构,并改变β相沿晶界网状分布为重溶后在α相晶内呈弥散分布. 相似文献
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为实现钨与铜的冶金可靠连接,采用浸渗法在纯钨材料表面制备一层含镍涂层。利用SEM及EDS研究不同浸渗熔体所对应的涂层/钨界面显微组织与成分分布。结果表明:于1 500℃温度通过Ni-Fe、Ni-Cu、Ni三种熔体浸渗,钨材表面对应形成的Ni-Fe涂层、Ni-Cu涂层、Ni涂层均与钨实现了冶金结合;Ni-Fe涂层对应的钨界面形成了由圆滑W颗粒相和少量粘结相组成的钨基高密度合金组织;在Ni涂层中,沿钨界面形成了厚1~2μm、由NiW和NiW2组成的化合物层。结合实验结果及W-Ni二元相图,分析了涂层/钨界面组织的形成机制。 相似文献
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