Cr3C2对Fe基合金激光熔覆层组织与性能的影响

为了研究Fe基、Cr3C2/Fe复合涂层的显微组织、抗高温氧化性能,以及Cr3C2/Fe复合涂层相结构演化规律,采用5kW CO2激光器在与Fe基合金成分相近的Q235钢表面熔覆Fe基合金涂层及Cr3C2/Fe基合金复合涂层的方法,进行了理论分析和实验验证,取得了相关试验数据。结果表明,Fe基合金涂层主要组成相为α-Fe,Cr23C6以及体心立方的α-Fe固溶体等;熔覆层主要以亚共晶方式结晶,在初生固溶体间存在层片状的共晶组织。Cr3C2/Fe基合金复合涂层组成为γ-Fe,α-Fe,Cr23C6,Cr3C2以及Cr7C3等。Fe基合金涂层由发达的α-Fe枝晶和其间共晶组织组成,Cr2C2/Fe基合金涂层典型组织为等轴晶以及细小的共晶组织;Cr3C2对熔覆层的组织有显著的改善作用,使其组织细化,促使组织由树枝晶向等轴晶转化;Cr3C2的加入可显著提高Fe基合金涂层的显微硬度、高温抗氧化性等物理性能。这一结果对以后相关的Fe基合金激光熔覆以及激光表面改性研究有一定的帮助。

Effect of Cr3C2 on Microstructure and Properties of Fe-based Alloy Coating by Laser Cladding

In order to study microstructure,high temperature oxidation resistance of Fe-based, Cr3C2/Fe composite coating, as well as phase structure evolution of Cr3C2/Fe composite coating, Fe-based alloy and Cr3C2/Fe-based alloy composite coatings were obtained on Q235 whose composition is similar with Fe-based alloy with a SkW CO2 laser.Then relevant test data were obtained and theoretical analysis was conducted.Results show that; the Fe-based alloy coating is mainly composed of phase α-Fe, Cr23C6,as well as the body-centered cubic α-Fe solid solution, etc.;the cladding layer mainly crystallizes in sub-eutectic crystallization way, there exists lamellar eutectic crystal organization between the primary solid solution.The main composition of Cr3C2/Fe-based alloy composite coating are γ-Fe,α-Fe, Cr23C6,Cr3C2,Cr7C3 and so on. The Fe-based alloy coating is composed of well-developed c}-Fe dendrites and the eutectic structure during the composition, Cr3C2/Fe-based alloy coating typical organizations are equiaxed grains, as well as small eutectic. Cr3C2 pairs play a major role in promoting the organization from dendrite to equiaxed transformation; Cr3C2 can significantly increase the micro-hardness, high temperature oxidation resistance and other physical properties of Fe-based alloy coating. The results have certain assistance for subsequent Fe-based alloy laser claddinc and laser surface modiCcation.