Study on microstructure and bending properties of NbC/Fe cluster-reinforced steel-based laminated composite
Yutong Yu, Shaoxiong Zhang, Lisheng Zhong, Chao Deng, Rui Shan, Yanwei Wang, Jianhong Peng, Yunhua Xu
Abstract
At present, the research on NbC reinforced metal matrix composites has been proofread, but little attention has been paid to the effect of Nb/C ratio on composites. The effects of different atomic ratios of Nb/C (Nb/C = 1:0.5, 1:1) on the microstructure and mechanical properties of NbC/Fe cluster-reinforced steel-based laminated composite were investigated through experiments and first-principles methods at 1200 °C. For Nb/C = 1:0.5, the transition-zone Laves phase Nb2C, NbC/iron-poor zone, and NbC/iron-rich zone were formed on the outside of the Nb particles. When the Nb/C atomic ratio increased to 1:1, the Nb atoms reacted completely to form NbC, and Nb2C was minimized. For Nb/C = 1:1, the deflections of the three- and five-layer composites increased by 112.34 % and 56.79 %, respectively, compared with those of the corresponding layers of T10 steel. The strengthening and toughening mechanisms of the NbC/Fe cluster-reinforced steel-based laminated composites were derived by observing the crack-extension paths. A first-principles approach showed that the NbC chemical bonds were mainly strong Nb–C covalent bonds, Nb–Nb metallic bonds, and some Nb–C ionic bonds. The chemical bonding of Nb2C comprised Nb–C covalent bonds, strong Nb–Nb metallic bonds, and a large number of Nb–C antibonding states. The advantages of NbC in terms of its thermodynamic and mechanical properties have also been determined.