Liu Lanyi, Huang Xiaoyang, Wang Guocheng, Zhang Xiaoyong, Zhou Kechao, Wang Bingfeng
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
The Powder Metallurgy Research Institute, Central South University, Changsha 410083, China.
Materials (Basel). 2025 Jun 26;18(13):3032. doi: 10.3390/ma18133032.
Functionally graded materials (FGMs) are fabricated on Ti-6Al-4V alloy surfaces to improve insufficient surface hardness and wear resistance. Microstructure and mechanical properties and strengthening-toughening mechanisms of FGMs were investigated. The FGM cladding layer exhibits distinct gradient differentiation, demonstrating gradient variations in the nanoindentation hardness, wear resistance, and Al/V elemental composition. Molten pool dynamics analysis reveals that Marangoni convection drives Al/V elements toward the molten pool surface, forming compositional gradients. TiN-AlN eutectic structures generated on the FGM surface enhance wear resistance. Rapid solidification enables heterogeneous nucleation for grain refinement. The irregular wavy interface morphology strengthens interfacial bonding through mechanical interlocking, dispersing impact loads and suppressing crack propagation. FGMs exhibit excellent wear resistance and impact toughness compared with Ti-6Al-4V titanium alloy. The specific wear rate is 1.17 × 10 mm/(N·m), dynamic compressive strength reaches 1701.6 MPa, and impact absorption energy achieves 189.6 MJ/m. This work provides theoretical guidance for the design of FGM strengthening of Ti-6Al-4V surfaces.
在Ti-6Al-4V合金表面制备功能梯度材料（FGMs）以改善其表面硬度不足和耐磨性。研究了FGMs的微观结构、力学性能及强韧化机制。FGM熔覆层呈现出明显的梯度分化，在纳米压痕硬度、耐磨性和Al/V元素组成方面表现出梯度变化。熔池动力学分析表明，马兰戈尼对流将Al/V元素驱向熔池表面，形成成分梯度。FGM表面生成的TiN-AlN共晶结构提高了耐磨性。快速凝固实现了异质形核以细化晶粒。不规则的波浪状界面形态通过机械互锁增强了界面结合力，分散了冲击载荷并抑制了裂纹扩展。与Ti-6Al-4V钛合金相比，FGMs具有优异的耐磨性和冲击韧性。其比磨损率为1.17×10⁻⁶mm³/(N·m)，动态抗压强度达到1701.6MPa，冲击吸收能量为189.6J/m²。这项工作为Ti-6Al-4V表面FGM强化设计提供了理论指导。
