稳恒磁场设计及电流强度对激光熔覆Fe55涂层微结构的影响

发布时间：2018-07-14 20:42

【摘要】：利用自行设计的稳恒磁场装置以辅助激光熔覆工艺,通过调节电流强度获得相应的稳恒磁场作用于激光熔池,在45钢基材表面制备了Fe55合金涂层。借助扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射(XRD)等表征手段分析了稳恒磁场作用下Fe55合金涂层的微观形貌、化学组成和物相结构。结果表明,Fe55合金涂层主要由γ-(Fe,Cr)和(Fe,Ni)固溶体、(Cr,Fe)_(23)C_6碳化物及少量Cr9.1Si0.9组成。与未施加磁场相比,稳恒磁场作用下的激光熔覆Fe55涂层,枝晶间Cr元素含量更高,枝晶内Fe元素含量也有所增加。稳恒磁场在一定程度上促进了激光熔池中的传质过程,有助于Fe,Cr元素扩散和(Fe,Cr)固溶体的形成。当电流强度为4.0A时,外加磁场大大降低了熔池内固-液界面前沿的温度梯度,增加了液态金属熔池的形核率,涂层中大量柱状枝晶和树枝晶转变为方向各异的等轴晶,涂层组织得到了明显优化。
[Abstract]:Fe55 alloy coating was prepared on the surface of 45 steel substrate by using the self-designed steady magnetic field device to assist the laser cladding process and the corresponding steady magnetic field acting on the laser melting pool by adjusting the current intensity. The microstructure, chemical composition and phase structure of Fe55 alloy coating under steady magnetic field were analyzed by means of scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the coating is mainly composed of 纬-(Feo Cr) and (Fen Ni) solid solution, (Crnfe) 23 C 6 carbides and a small amount of Cr 9.1Si 0.9. Compared with that without magnetic field, laser cladding Fe 55 coating under steady magnetic field has higher Cr content between dendrites and higher Fe content in dendrite. The steady magnetic field promotes the mass transfer process in the laser molten pool to a certain extent, and is helpful to the diffusion of Fe ~ (2 +) Cr and the formation of (Fe _ (Cr) _ (Cr) solid solution. When the current intensity is 4.0 A, the temperature gradient at the front of the solid-liquid interface in the molten pool is greatly reduced by the applied magnetic field, the nucleation rate of the molten metal pool is increased, and a large number of columnar dendrites and dendrites in the coating are transformed into equiaxed crystals with different directions. The coating structure was obviously optimized.
【作者单位】：昆明理工大学材料科学与工程学院;
【基金】：国家自然科学基金(11674134,61368003) 云南省应用基础研究计划重点项目((P0120150044) 云南省中青年学术和技术带头人后备人才资助项目(2014HB007)
【分类号】：TG174.4

【相似文献】