Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex...Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex thermal profiles during solidification.Here,wire arc additive manufacturing(WAAM)process was used to fabricate a steel-nickel structural component,whose average tensile strength of 634 MPa significantly exceeded that of feedstock materials(steel,537 MPa and nickel,455 MPa),which has not been reported previously.The as-fabricated sample exhibited hierarchically structural heterogeneity due to the interweaving deposition strategy.The improved mechanical response during tensile testing was due to the inter-locking microstructure forming a strong bond at the interface and solid solutions strengthening from the intermixing of the Fe and Ni increased the interface strength,beyond the sum of parts.The research offers a new route for producing high-quality steel-nickel dissimilar structures and widens the design opportunities of monolithic components,with site-specific properties,for specific structural or functional applications.展开更多
针对厚度6 mm N06200镍基合金和S32168不锈钢手工TIG焊接试板,采用三种热处理工艺对不同状态下焊接接头的微观组织、力学性能、断口形貌及耐腐蚀性能进行分析对比。结果表明:N06200镍基合金与S32168不锈钢TIG焊接接头组织为等轴晶奥氏...针对厚度6 mm N06200镍基合金和S32168不锈钢手工TIG焊接试板,采用三种热处理工艺对不同状态下焊接接头的微观组织、力学性能、断口形貌及耐腐蚀性能进行分析对比。结果表明:N06200镍基合金与S32168不锈钢TIG焊接接头组织为等轴晶奥氏体和垂直于熔合线方向生长的树枝晶组成;1 050℃热处理后焊接接头的抗拉强度最高为736 MPa,与N06200母材强度接近,较未热处理的焊接接头的抗拉强度(675 MPa)提高了9.05%;未热处理和1050℃热处理后的焊接接头断裂方式都为韧性断裂,1 150℃热处理后的焊接接头断裂方式为韧性+脆性混合型断裂,焊缝区域硬度高于其他区域;界面组织为靠近N06200镍基合金侧的IMCs为NiFe和Ni_(2)Cr,靠近S32168不锈钢侧的IMCs为FeCr和Ni_(3)Fe;NiFe相晶粒的主要织构为<011>丝织构,Ni_(3)Fe相晶粒的取向较明显,为强烈的<111>丝织构组成。展开更多
基金carried out at the Welding Engineering Research Group,University of Wollongong,and it was supported by China Scholarship Council(No.201506680056)the National Natural Science Foundation of China(No.51805085)。
文摘Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex thermal profiles during solidification.Here,wire arc additive manufacturing(WAAM)process was used to fabricate a steel-nickel structural component,whose average tensile strength of 634 MPa significantly exceeded that of feedstock materials(steel,537 MPa and nickel,455 MPa),which has not been reported previously.The as-fabricated sample exhibited hierarchically structural heterogeneity due to the interweaving deposition strategy.The improved mechanical response during tensile testing was due to the inter-locking microstructure forming a strong bond at the interface and solid solutions strengthening from the intermixing of the Fe and Ni increased the interface strength,beyond the sum of parts.The research offers a new route for producing high-quality steel-nickel dissimilar structures and widens the design opportunities of monolithic components,with site-specific properties,for specific structural or functional applications.
