In the present study, optimization of various laser-processing parameters for the deposition of thick SiC coating on zircaloy-4 (Zry-4) tube is studied in view of the development of accident tolerant fuel clad material for current and future nuclear reactors with the enhanced safety. The SiC coatings are deposited using laser directed energy deposition (LDED). It is found to be quite challenging to deposit desired SiC coating on a thin (~400 μm) substrate of Zry-4 tubes due to either its excessive melting or damage. This is minimized largely by cooling the tube from inside by passing Ar gas (20 l min⁻¹). It is observed that different processing parameters play a vital role on homogeneity, uniformity and defects-free SiC coatings as well as on the melting and oxidation of Zry-4 substrate. A uniform and homogeneous coating of SiC is deposited on Zry-4 at the optimized laser power density of 4.52 kW cm⁻², powder feed rate of 2.71 g min⁻¹and scan speed of 325 mm min⁻¹. The interface between SiC coatings and substrate is characterized using different techniques such as optical microscopy, scanning electron microscopy and X-ray diffraction to access the homogeneity, uniformity, defects and to identify the different phases formed in the coated layer. Coated layer is found to be consisting of Zr(α), SiC, ZrSi₂, ZrSi and ZrC types of phases and the same is also confirmed by the ThermoCalc(R) based ternary phase diagram. Further, the effect of processing parameters on substrate melting and the nature of SiC coating is explained by simulating the substrate temperature using COMSOL^@ multi-physics. To the author's best knowledge, this would be the first study to report the laser directed energy deposition of SiC on Zry-4 alloy.

在本研究中，鉴于目前和未来的核反应堆采用耐事故的燃料包覆材料的发展，研究了在zircaloy-4（Zry-4）管上沉积厚SiC涂层的各种激光工艺参数的优化。增强安全性。使用激光定向能量沉积（LDED）沉积SiC涂层。已经发现，由于Zry-4管的过度熔化或损坏，在薄（〜400μm）的Zry-4管基板上沉积所需的SiC涂层非常困难。通过在内部通入Ar气（20 l min ^-1）。可以看出，不同的工艺参数对均匀性，均匀性和无缺陷的SiC涂层以及Zry-4基板的熔化和氧化起着至关重要的作用。在Zry-4上以4.52 kW cm ^-2的最佳激光功率密度，2.71 g min ^-1的粉末进料速率和325 mm min ^-1的扫描速度沉积均匀且均匀的SiC涂层。SiC涂层与基材之间的界面使用不同的技术进行表征，例如光学显微镜，扫描电子显微镜和X射线衍射，以获取均质性，均匀性，缺陷并识别涂层中形成的不同相。发现涂层由Zr（α），SiC，ZrSi _2组成，ZrSi和ZrC相的类型，也可以通过基于ThermoCalc（R）的三元相图来确认。此外，处理在衬底熔化和SiC涂层的性质参数的效果是通过使用模拟COMSOL衬底温度解释^@多物理。据作者所知，这将是第一个报道Zry-4合金上SiC激光定向能量沉积的研究。