Modelling and Characterisation of Electrical Discharge TiC-Fe Cermet Coatings
Modelling and Characterisation of Electrical Discharge TiC-Fe Cermet Coatings
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DOI：
10.1016/j.procir.2017.12.017
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
S. J. Algodi;J. Murray;A. Clare;P. Brown
中科院分区：
文献类型：
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作者：
S. J. Algodi;J. Murray;A. Clare;P. Brown
通过电火花(ED)方法产生的涂层可以增强经过先前的电火花加工工艺步骤的部件的功能。然而，由于对能源和材料之间的基本相互作用缺乏了解，这些方法的工业应用一直受到限制。针对TiC牺牲电极沉积在不锈钢表面的情况，采用有限差分方法对二维非稳态热传导进行了数值模拟和数值求解，得到了电火花涂层(EDC)表面的热分布和预期微观组织。通过与实验数据和文献数据的比较，验证了该模型的有效性。此外，在干滑动磨损条件下对TiC涂层进行了摩擦磨损试验，以评价其与Al_2O_3对偶面球面的摩擦学性能。预计在固定脉冲开启时间为8μS时，电流增大时，转移到工件上的有效能量在17%到23%之间变化，在2到19A之间变化；在固定电流为10A时，增大脉冲开启时间时，转移到工件上的有效能量在7%到53%之间变化，从2到到μS，在固定电流为10A时，涂层由金属基复合材料组成，具有复杂的带状细晶组织和不同的涂层冷却速度。304不锈钢(304-SS)表面TiC基电火花涂层的磨损率比基体低两个数量级。
The creation of coatings via Electrical Discharge (ED) methods can enhance the functionality of components which are subject to prior ED machining process steps. However, the industrial application of these methods has been limited due to poor understanding of the fundamental interaction between energy source and material. In this paper, for the case of a TiC sacrificial electrode deposited onto a stainless steel, 2D transient heat transfer is modelled and solved by a finite difference method to estimate the effective fraction of total energy transferred to the workpiece, as well as heat distribution and expected microstructure upon ED coating (EDC). The model was validated via comparison with experimental data, as well as data in literature. In addition, a TiC coating was tested under dry sliding wear conditions to evaluate its tribological properties against an Al2O3counter face sphere using ball-on-flat geometry. The effective amount of energy transferred to the workpiece is predicted to vary between 17% and 23% for increasing current, from 2 to 19 A, at fixed pulse-on time of 8 μs; and between 7% and 53% for increasing pulse-on time, from 2 to 64 μs, at fixed current of 10 A. Backscattered electron (BSE) imaging showed that the coatings comprised a metal matrix composite, with a complex banded fine-grained microstructure and different cooling rate across the coating. A TiC-based ED coating on 304 stainless steel (304-SS) yielded a wear rate two orders of magnitude lower than that of the substrate only.