Microstructure, microhardness, and tensile properties of hot-rolled Al6061/TiB2/CeO2 hybrid composites

T1B2 and CeO2 particle-reinforced A16061 hybrid composites were manufactured using stir casting and hot rolling techniques. The base alloy and composites were hot-rolled at 500°C and a 50% reduction was achieved through 12 passes. The effect of varying TB2 and CeO2 particle additions on the microstructure and mechanical properties of the Al6061 matrix was studied. Scanning electron microscopy showed uniform dispersion of both the reinforcements, with good interfacial bonding. Microhardness and tensile properties like yield and tensile strength were found to be higher for hybrid composite with 2.5% TiB2 and 2.5% CeO2 compared to Al6061 alloy and other hybrid composites. The increased tensile strength is attributed to good dispersion and interfacial bonding between the particles and Al6061 matrix. Fracture analysis using a scanning electron microscope revealed ductile fracture for the Al6061 alloy and mixed characteristics of ductile-brittle fracture for hybrid composites.

Size Effect of CeO2 Particle On Nanoscale Single-Asperity Sliding Friction

The size of abrasive particle has a great impact on the fundamental friction behavior and mechanical properties of the abrasive during ultra-precision polishing performance. Here, the size effect of the tribological behavior and mechanical properties of CeO2 single abrasive were studied. Experimental results show that the size effect plays a role on coefficient of friction (COF) of each regime in single-asperity sliding friction, especially in ploughing and cutting regimes. The residual depth of the scratch and COF both decrease with the increase of the CeO2 tip radius. These results relate to the mechanical properties of CeO2 nanoparticles. We found that the effective modulus increases with the decrease of abrasive size, which corresponds to the size effect of the single-asperity sliding friction experiment.

Synthesis and Characterization of Fibular PANI/Nano-CeO2 Composites

The fibular PANI/ nano-CeO2 composites were synthesized via chemical oxidation of aniline using nano-CeO2 as an oxidant, and nano-CeO2 was prepared by hydrothermal treatment. Sphere-like morphology and fibers of PANI/ nano-CeO2 composites were obtained. The resulting composites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR). The results showed that chemical bonds existed between two phases. The acid concentration and nano-CeO2 particles affected the crystallinity of PANI fibers. The morphology of PANI was formed from the ball gradually developing into the fibular with rising of acid concentration. The regular crystalline structure of fibular was easy to form with a reducing CeO2 particle size.