Ding Yu, Du Chengchao, Wang Xiaojing, Zhang Binbin
School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212013 China.
School of Material Science and Engineering, Jiangsu University, Zhenjiang, 212013 China.
Adv Compos Hybrid Mater. 2021;4(1):205-211. doi: 10.1007/s42114-020-00194-w. Epub 2021 Jan 4.
The extreme high-speed laser cladding (EHLA) was employed to fabricate a 1Cr17Ni2 coating. The solidification behavior, phase transformation, and interfacial metallurgical bonding of the coating were systematically investigated. The results showed that the major phase transformation during solidification was liquid to γ-Fe. The large temperature gradient of melting pool and slow grow rate of γ-Fe grain contributed to the fine columnar prior austenite grain (PAG) in coating. The largest thermal conductivity of [0 0 1] crystal direction determined the preferential [0 0 1] orientation of PAG perpendicular to the liquid-solid interface. A thin γ-Fe layer (approximately 5 μm) was observed between coating and substrate. The Bain relationship between interfacial γ-Fe layer and substrate and the K-S relationship between interfacial γ-Fe layer and coating contributed to the reliable metallurgical bonding between coating and substrate. The shear test revealed the high shear strength (approximately 92% of that of substrate) and weaker plastic deformation ability of the interface.
The interfacial γ-Fe layer effectively combined the coating and substrate via K-S and Bain crystallographic relationship.
采用超高速激光熔覆（EHLA）制备1Cr17Ni2涂层。系统研究了涂层的凝固行为、相变及界面冶金结合。结果表明，凝固过程中的主要相变为液相到γ-Fe。熔池的大温度梯度和γ-Fe晶粒的缓慢生长速率导致涂层中形成细小的柱状先共析奥氏体晶粒（PAG）。[0 0 1]晶体方向的最大热导率决定了PAG优先垂直于液-固界面的[0 0 1]取向。在涂层与基体之间观察到一层约5μm厚的γ-Fe层。界面γ-Fe层与基体之间的贝恩关系以及界面γ-Fe层与涂层之间的K-S关系有助于涂层与基体之间可靠的冶金结合。剪切试验表明，界面具有较高的剪切强度（约为基体剪切强度的92%）和较弱的塑性变形能力。
界面γ-Fe层通过K-S和贝恩晶体学关系有效地结合了涂层和基体。
