Nanofluid minimum quantity lubrication (NMQL) has better stability, higher thermal conductivity, and excellent lubrication performance compared with traditional flood lubrication. The heat transfer model and finite difference model were established to verify the feasibility of NMQL conditions in grinding cemented carbide. Based on them, the grinding temperature of cemented carbide is calculated numerically. Results show that the grinding zone temperatures of flood grinding and NMQL are lower, 85.9 °C and 143.2 °C, respectively. Surface grinding experiments of cemented carbide YG8 under different working conditions are carried out. Dry grinding (227.2 °C) is used as the control group. Grinding zone temperatures of flood grinding, minimum quantity lubrication, and NMQL decrease by 64.2%, 39.5%, and 20.4%, respectively. The error is 6.3% between theoretical calculation temperature and experimental measurement temperature. Based on machining process parameters (specific grinding force, force ratio) and experimental results (microstructure of grinding wheel, workpiece, and grinding debris), the effects of different working conditions on wheel wear are studied. NMQL achieves the highest G ratio of 6.45, the smallest specific grinding force, and the smallest Fn/Ft ratio of 2.84, which further proves that NMQL is suitable for grinding cemented carbide.

Piezoelectric composites are considered excellent core materials for fabricating various ultrasonic devices. For the traditional fabrication process, piezoelectric composite structures are mainly prepared by mold forming, mixing, and dicing-filing techniques. However, these techniques are limited on fabricating shapes with complex structures. With the rapid development of additive manufacturing (AM), many research fields have applied AM technology to produce functional materials with various geometric shapes. In this study, the Mask-Image-Projection-based Stereolithography (MIP-SL) process, one of the AM (3D-printing) methods, was used to build BaTiO₃-based piezoelectric composite ceramics with honeycomb structure design. A sintered sample with denser body and higher density was achieved (i.e., density obtained 5.96 g/cm³), and the 3D-printed ceramic displayed the expected piezoelectric and ferroelectric properties using the complex structure (i.e., piezoelectric constant achieved 60 pC/N). After being integrated into an ultrasonic device, the 3D-printed component also presents promising material performance and output power properties for ultrasound sensing (i.e., output voltage reached 180 mVpp). Our study demonstrated the effectiveness of AM technology in fabricating piezoelectric composites with complex structures that cannot be fabricated by dicing-filling. The approach may bring more possibilities to the fabrication of micro-electromechanical system (MEMS)-based ultrasonic devices via 3D-printing methods in the future.