No abstract

In this paper, two kinds of different biodiesel were tested in terms of their impact on wear resistance of Si-DLC coated 100Cr6 flat worn by an oscillating 100Cr6 ball. The knowledge about the tribological behaviour of different types of biodiesel is rare. Rape and soybean are two of the most common natural sources for biodiesel production. Also, if the quality of biodiesel seems to be similar and, according to the demands, biodiesel from different natural origin could affect changes in the tribological behaviour. Although, soybean methyl ester (SME) gives the best results at room temperature wear tests, 150 ∘ C SME reaches wear rates of Si-DLC flat against 100Cr6 ball almost double as high as rapeseed methyl ester (RME). It is evident that, with increasing fraction of oxidation stabilizer C 23 H 32 O 2 , the wear rate increases. For silicon doped hydrogenated diamond-like carbon is especially suitable, for use in biodiesels, where certain fraction of humidity, dissociated water, or polar functional groups may present.

Aluminum alloy AA5754 is used for many technical and industrial applications. Twin roll casting is unique among the casting processes in that it is a combined solidication/deformation technique. The simultaneous solidication and hot rolling produces characteristic microstructure with a ne cell size and intermetallic particle distribution with some residual structure. In the study, rst AA5754 alloy (tread and plain sheet) strips were fabricated by using a twin-roll caster equipped with water-cooled steel-rolls. To reduce the thickness of the strip, cold rolling process was applied until strip thickness got 3 mm. After homogenization step the strips were cut in to smaller specimens and annealed at 260• C, 285 520• C for 3 hours to obtain the desired temper conditions. Mechanical properties were investigated after processes.Tensile, hardness and bending tests were applied to monitor the eect of annealing after cold rolling process.