Search

Effects of different stacking sequences covering one external layer of basalt (HB1), three external layers of basalt fabrics (HB3) and three external layers of carbon fabrics (HC3) using epoxy on wear properties were investigated with a reciprocating pin-on-plate configuration under various conditions. Worn surfaces of composites were examined by scanning electron microscopy (SEM). Mechanical properties such as hardness and three point-bending tests were conducted. The wear resistance of composites decreased significantly with increasing speed. The speed was more effective than that of the stacking sequence on the dry wear. The wear resistance of HC3 composite was better than those of the others due to its superior mechanical properties. Furthermore, worn surface's examination exhibited the fiber fracture and oxidative wear for HB1 samples, matrix wear was dominated upon increasing speed for HB3 hybrid composites, but craters and deformed layer covering the mixtures of fibers and resin were evidenced for HC3 hybrid composites. [ABSTRACT FROM AUTHOR]

The present study investigates on the two body abrasive wear behavior of Al-6082 alloy, Al 6082 alloy-10% SiC (Al- SiC) composites and Al 6082 alloy - 5% SiC-5% Gr (Al-SiC-Gr) hybrid composites. These composites were prepared by stir casting process. The wear tests of these materials were conducted at load of 5 - 15 N and sliding distance of 50 - 75 m at grit size of 200 µm. The wear response influenced by these parameters was analyzed and compared with each other. The results show that graphitic composites yielded better wear resistance compared to alloy and single SiC reinforced composite. Worn surfaces of samples were observed by using scanning electron microscope (SEM) and it was revealed that the wear grooves appeared to be narrow and shallow in case of hybrid composites. [ABSTRACT FROM AUTHOR]

A high-carbon, high-silicon steel (1.21 wt% C, 2.56 wt% Mn, 1.59 wt% Si) was subjected to quenching from 900 and 1000 °C, resulting in microstructures containing 60 and 94% of retained austenite, respectively. Subsequent abrasive wear tests of quenched samples were performed using two-body abrasion and three-body abrasion testing machines. Investigations on worn surface and subsurface were carried out using SEM, XRD, and microhardness measurement. It was found that the highest microhardness of worn surface (about 1400 HV0.05) was achieved on samples quenched from 900 °C after three-body abrasion. Microhardness of samples after two-body abrasion was noticeably smaller. with a maximum of about 1200 HV0.05. This difference correlates with microstructure investigations along with XRD results. Three-body abrasion has produced a significantly deeper deformed layer; corresponding diffractograms show bigger values of the full width at half maximum parameter (FWHM) for both α and γ alone standing peaks. The obtained results are discussed in the light of possible differences in abrasive wear conditions and differing stability of retained austenite after quenching from different temperatures. It is shown that a structure of metastable austenite may be used as a detector for wear conditions, as the sensitivity of such austenite to phase transformation strongly depends on wear conditions, and even small changes in the latter lead to significant differences in the properties of the worn surface. [ABSTRACT FROM AUTHOR]