The freckle formation and their phase characterizatics in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in an Inconel 625 allay...The freckle formation and their phase characterizatics in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in an Inconel 625 allay. These results show that in freckle areas a large number of M6C, MC, Laves and δ phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and Nb during solidification, which results in almost of these freckle areas covered by these complex precipitated phases and induces small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give a reasonable interpretation of the freckle feature for this alloy.展开更多
Inconel 625+WC composite coatings were prepared on the surface of 2Cr13 steel by laser cladding.The microstructure,microhardness and corrosion resistance of the composite coatings with different WC contents were inves...Inconel 625+WC composite coatings were prepared on the surface of 2Cr13 steel by laser cladding.The microstructure,microhardness and corrosion resistance of the composite coatings with different WC contents were investigated in detail.The results show that the phase compositions of the composite coatings are mainly y-(Ni,Fe)and various carbides.The content of WC has a significant effect on the microstructure of the cladding layers.When the WC content is 10 wt%and 15 wt%,the cladding layer has developed columnar dendrites.However,the 20 wt%WC coating is mainly composed of cellular dendrites and columnar dendrites.With the increase in WC content,the average hardness of the composite coating gradually increases.The average hardness of 20 wt%WC coating is the highest(HV_(1)536.98),which is a factor of2.64 greater than that of the 2 Cr13 steel matrix.Electrochemical results show that all the composite coatings have better corrosion resistance than 2 Cr13 steel in 0.5 mol·L^(-1) HCl solution.The composite coating with 10 wt%WC has the best corrosion resistance,its corrosion potential(E_(corr))is 0.78806 V higher than that of 2 Cr13 steel,and the corrosion current density(I_(corr))is only 0.86%that of 2 Cr13 steel.展开更多
基金The project was suppored by National Natural Science Foundation of China(No.50371006)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE,China.
文摘The freckle formation and their phase characterizatics in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in an Inconel 625 allay. These results show that in freckle areas a large number of M6C, MC, Laves and δ phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and Nb during solidification, which results in almost of these freckle areas covered by these complex precipitated phases and induces small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give a reasonable interpretation of the freckle feature for this alloy.
基金financially supported by the Natural Science Foundation of Inner Mongolia Autonomous Region(No.2017MS(LH)0518)。
文摘Inconel 625+WC composite coatings were prepared on the surface of 2Cr13 steel by laser cladding.The microstructure,microhardness and corrosion resistance of the composite coatings with different WC contents were investigated in detail.The results show that the phase compositions of the composite coatings are mainly y-(Ni,Fe)and various carbides.The content of WC has a significant effect on the microstructure of the cladding layers.When the WC content is 10 wt%and 15 wt%,the cladding layer has developed columnar dendrites.However,the 20 wt%WC coating is mainly composed of cellular dendrites and columnar dendrites.With the increase in WC content,the average hardness of the composite coating gradually increases.The average hardness of 20 wt%WC coating is the highest(HV_(1)536.98),which is a factor of2.64 greater than that of the 2 Cr13 steel matrix.Electrochemical results show that all the composite coatings have better corrosion resistance than 2 Cr13 steel in 0.5 mol·L^(-1) HCl solution.The composite coating with 10 wt%WC has the best corrosion resistance,its corrosion potential(E_(corr))is 0.78806 V higher than that of 2 Cr13 steel,and the corrosion current density(I_(corr))is only 0.86%that of 2 Cr13 steel.
基金Innovation Foundation of Southwest Petroleum University(CX2014BY05)Open Foundation of Education Department Key Laboratory of Oil and Gas Equipment(OGE201401-01)
文摘基于中心复合试验设计方法,采用热丝脉冲TIG(tungsten inert gas arc welding)工艺,在AISI 4130基体上堆焊Inconel 625合金层。借助响应面法建立了焊缝几何特征与工艺参数之间的数学模型。根据优化后的工艺参数,获得了平坦、连续、无缺陷的多道两层堆焊层。堆焊层微观组织主要由柱状晶组成,在融合界面附近存在少量的平面晶与胞状晶,其顶部组织为等轴晶与转向晶。利用动态极化曲线法对基体与堆焊层的耐腐蚀性能进行了评价。结果表明:堆焊层的耐腐蚀性随着Fe含量的增加而降低,但增加堆焊层的层数可以显著提高耐腐蚀性能。而且,两层堆焊层试样与铸态Inconel 625的耐腐蚀性能基本相当。
