FeAlCuCrNiNbx系高熵合金堆焊层的组织及性能分析

Microstructure and property analysis of FeAlCuCrNiNb_x high-entropy alloy surfacing layer

为了研究Nb元素含量对FeAlCuCrNiNb_x(x=0.4,0.6,0.8,1.0,x为摩尔比)高熵合金的组织结构及性能的影响,采用熔化极气体保护焊技术在碳钢板表面制备出FeAlCuCrNiNb_x高熵合金堆焊层,而后对堆焊层进行显微组织、物相组成、显微硬度、耐磨性和耐蚀性分析.结果表明,FeCuCrAlNiNb_x高熵合金堆焊层呈现以Fe-Cr相为基的BCC固溶体和少量MC共晶碳化物.组织为典型的枝晶结构,由灰色的枝晶(DR)及白色的枝晶间(ID)结构组成.对于耐磨性,加入适量的Nb元素可以显著提高堆焊层的显微硬度和耐磨性,当Nb摩尔比为0.8时,显微硬度最高,耐磨性最好,最大硬度值达到602 HV,磨损量最小为0.30 g.对于耐蚀性,加入一定量的Nb元素后极化曲线中自腐蚀电流密度减小,腐蚀速率减慢,耐蚀性增强,均优于304不锈钢,当Nb摩尔比为1.0时,堆焊层合金耐蚀性最好.

In order to study the effect of Nb element content on the structure and properties of FeAlCuCrNiNb_x(x =0.4,0.6,0.8,1.0) high-entropy alloy, the FeAlCuCrNiNb_x highentropy alloy was prepared on the surface of carbon steel sheet by the technique of gas metal arc welding. The microstructure,phase composition, microhardness, wear resistance and corrosion resistance of surfacing layer were analyzed. The results show that: the surfacing layer of FeCuCrAlNiNb_x highentropy alloy is composed of Fe-Cr phase-based BCC solid solution and a few of MC eutectic carbide. The structure is a typical dendrite structure, which is composed of gray dendrite(DR) and white interdendrite(ID) structure. For wear resistance, addition amounts of Nb can significantly improve the microhardness and wear resistance of surfacing layer. The optimal properties of surface layer were obtained when the molar ratio of Nb element is 0.8, which maximum microhardness value is 602 HV, the minimum wear is 0.30 g,respectively. For the corrosion performance, with increase of Nb element addtion amounts, the self-corrosion current density become to reduce, the corrosion rate become to slow, and the corrosion resistance enhances. All of these are better than 304 stainless steel. When the molar ratio of Nb element is 1.0, the corrosion resistance of the surfacing alloy is the best.