Layered Microstructure Distribution and Forming Mechanism of Laser-Processed Ni-Fe-B-Si-Nb-C Amorphous Composite Coatings
Layered Microstructure Distribution and Forming Mechanism of Laser-Processed Ni-Fe-B-Si-Nb-C Amorphous Composite Coatings
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DOI：
10.2320/matertrans.m2016189
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发表时间：
2016-10
影响因子：
1.2
通讯作者：
Shujin Chen;Ruifeng Li;Q. Zheng;Zhuguo Li
中科院分区：
文献类型：
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作者：
Shujin Chen;Ruifeng Li;Q. Zheng;Zhuguo Li
采用激光熔覆技术制备了镍基非晶复合涂层。用扫描电镜（SEM）和透射电镜（TEM）观察了其微观结构。采用有限元法模拟了激光重熔过程中的冷却行为。结果表明，共形成了四种不同显微结构的涂层。该层由粗枝晶、ne枝晶、等轴枝晶和NbC颗粒/非晶相层组成。在包覆/重熔界面处观察到NbC颗粒的异质形核。非晶相是激光重熔层中的主要相。数值模拟结果表明，冷却速率沿涂层表面沿着深度方向逐渐减小。冷却速率约为104 K/s。当冷却速率高于临界冷却速率阈值时，激光重熔后的重熔层中形成非晶相。[doi：10.2320/matertrans.M2016189]
A Ni-based amorphous composite coating was fabricated via laser processing. Its microstructure was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cooling behavior during the laser remelting process was simulated using a nite element method. The results indicated that four layers with different microstructures were formed. The layers consist of coarse dendrites, ne dendrites, equiaxed dendrites, and a layer of NbC particles/amorphous phase. Heterogeneous nucleation from NbC particles was observed at the clad/remelt interface. An amorphous phase was the primary phase in the laser remelted layer. Numerical simulation results showed that the cooling rates decreased along the depth direction from the top coating surface. The cooling rate was on the order of 104 K/s. When the cooling rate was higher than the critical cooling rate threshold, an amorphous phase was formed in the remelted layer after the laser remelting process. [doi:10.2320/matertrans.M2016189]