Laser beam profile modulation for microstructure control in laser cladding of an NiCrBSi alloy
Laser beam profile modulation for microstructure control in laser cladding of an NiCrBSi alloy
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DOI：
10.1016/j.surfcoat.2014.03.018
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发表时间：
2014-06-15
影响因子：
5.4
通讯作者：
Liu, C. S.
中科院分区：
文献类型：
--
作者：
Shang, S.;Wellburn, Dan;Liu, C. S.
采用可变光强分布的圆形激光束，研究了光强分布整形对NiCrBSi型耐蚀耐磨合金激光熔覆层组织形成的影响。利用可变光束轮廓调制器对高功率光纤传输激光器的原始光束轮廓输出进行了控制。所产生的光束轮廓采取具有均匀强度中心填充的聚焦环形环的形式。通过调节可变光束轮廓调制器中的光学元件来改变环形环和中心填充物的相对强度。三个所产生的光束轮廓中使用的激光熔覆的单轨道沉积物的NiCrBSi基耐腐蚀和耐磨合金Cr5钢。利用XRD、SEM和EDS分析了激光熔覆层的微观组织。结果发现，可以通过改变激光束轮廓来控制通过熔覆层的深度的显微组织中的硬质相的规模和分布的变化。使用传统的顶帽型光束轮廓，微观结构从包覆层的下部的非常粗糙变化到上部的精细。创建具有优选地在外边缘处比在中心处更大的强度的光束轮廓允许熔覆层在整个层的深度上以更大的微观结构均匀性产生，并且鼓励熔覆层的表面附近的相对更大的硬枝晶相的生长。(C)2014爱思唯尔有限公司版权所有。
A circular laser beam with a variable intensity profile was used to investigate the effects of beam intensity profile shaping on the microstructure formation within laser clad layers of an NiCrBSi type corrosion and wear resistant alloy. The raw beam profile output of a high power, fibre delivered laser was manipulated using a variable beam profile modulator. The beam profiles generated took the form of a focussed annular ring with a uniform intensity central fill. The relative intensities of the annular ring and central fill were varied by an adjustment of the optical elements in the variable beam profile modulator. Three of the generated beam profiles were used in the laser cladding of single track deposits of an NiCrBSi based corrosion and wear resistant alloy on Cr5 steel. The microstructure throughout the laser clad layers was examined using XRD, SEM and EDS. It was found that the variations in the scale and distribution of hard phases in the microstructure through the depth of the clad layer can be controlled by varying the laser beam profile. Using a traditional top-hat type beam profile, the microstructure varied from very coarse in the lower part of the clad layer to fine in the upper part. Creating beam profiles with a preferentially greater intensity at the outer edge than at the centre allowed clad layers to be produced with greater microstructural homogeneity throughout the depth of the layer and encouraged the growth of comparatively larger hard dendrite phases near the surface of the clad layer. (C) 2014 Elsevier B.V. All rights reserved.