Purpose This research aims to describe the influence of weight per cent of graphite (Gr), applied load and sliding speed on the wear behavior of aluminum (Al) alloy A356 reinforced with silicon carbide (SiC) (10 Wt.%) and Gr (1 Wt.% and 5 Wt.%) particles. The objective is to analyze the effect of the aforementioned parameters on a specific wear rate. Design/methodology/approach These hybrid composites are obtained by means of the compo-casting process. Tribological analyses were conducted on block-on-disc tribometer at three different loads (10, 20 and 30 N) and three different sliding speeds (0.25, 0.5 and 1 m/s), at the sliding distance of 900 m, in dry sliding wear conditions. Optimization of the tribological behavior was conducted via the Taguchi method, and ANOVA was used for the analysis of the specific wear rate. Confirmation tests are used to foresee and check the experimental results. Examined samples were analyzed via a scanning electron microscope (SEM). Regression models for predicting specific wear rate were developed with Taguchi and ANN (artificial neural network) methods. Findings The biggest impact on value of specific wear rate has the load (43.006%), while the impact of Wt.% Gr (31.514%) was less. After comparison of the results, i.e. regression models, for predicting the specific wear rate, it was observed that ANN was more efficient than the Taguchi method. The specific wear rate of Al alloy A356 with SiC (10 Wt.%) and Gr (1 Wt.% and 5 Wt.%) decreases with a decrease in the load and weight per cent of Gr-reinforcing material, as well as with a decrease in sliding speed. Originality/value The results obtained in this paper using the Taguchi method and the ANN method are useful for improving and further investigating the wear behavior of the SiC- and Gr-reinforced Al alloy A356.

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Original scientific paper Taguchi method has been used to analyse the influence of the coefficient of the trochoid radius, the number of revolutions and the working pressure on the change in the flow rate and the volumetric efficiency of the trochoidal rotary pump with internal gearing. The coefficient of the trochoid radius, as a geometrical parameter and the number of revolutions and the pressure, as working parameters are considered influential factors in this paper. Taguchi robust design and orthogonal matrices have been applied to design the experiment and to determine the degree of the factors influence, as well as their optimum values. The highest values both for the flow rate and the volumetric efficiency have been obtained for the coefficient of the trochoid radius of 1.375, the number of revolutions of 2000 min −1 and for the working pressure of 1 bar. The conformation of the experiment shows that Taguchi method can be successfully used for selection of the optimal combination of parameters so that the maximum volumetric efficiency of the trochoid pump can be achieved. Keywords: ANOVA; flow rate; gerоtor; Таguchi method; trochoidal pump; volume efficiency Analiza protoka i volumenskog stupnja iskoristivosti trohoidne pumpe primjenom Taguči metodeIzvorni znanstveni članak Primjenom Taguči metode u radu je analiziran utjecaja koeficijenta polumjera trohoide, broja okretaja i radnog tlaka na promjenu protoka i volumenskog stupnja iskoristivosti trohoidne rotacijske pumpe s unutarnjim ozubljenjem. Koeficijent polumjera trohoide je geometrijski parametar, a broj okretaja i tlak su radni parametri koji predstavljaju utjecajne faktore u ovom radu. Primjenom metode Tagučijevog robusnog dizajna i ortogonalnih matrica formiran je eksperimentalni dizajn i određen je stupanj utjecaja faktora, kao i njihove optimalne vrijednosti. Za analizirane uvjete eksperimenta, najveće vrijednosti protoka i volimenskog stupnja iskoristivosti dobivene su za koeficijent polumjera trohoide 1.375, broj okretaja od 2000 min −1 i radni tlak od 1 bar. Potvrda eksperimenta pokazuje svrhovitost primjene Taguči metode za izbor optimalne kombinacije parametara u odnosu na maksimalni volumenski stupanj iskoristivosti trohoidne pumpe.

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Nanocomposites with aluminum base reinforced with nanoparticles, have wide application in many industries, for example, aerospace, marine, automobile, due to its lightweight, high tensile strength and high wear resistance, etc. The study of the microstructure, mechanical and tribological properties of the nanocomposite is very important in order to reliably and optimally carry out the design of new materials. In this study for the mechanical characterization of the A356 composites with a ceramic particle reinforcements nanoindentation was performed. Nanoindentaion is largely used for the analysis of mechanical properties. The samples of the nanocomposites were developed using 0, 0.2, 0.3 and 0.5 wt.% SiC, with an average size of particles of about 50 nm, produced by a compocasting process with pre-processing mechanical alloying. Nanoindentation was carried out based on Berkovich's test method with the indenter in shape of three sided diamond pyramid. The nanocomposite testing showed that the nanocomposites containing 0.5 wt.% of the reinforcement have slightly higher tensile strength and a lower value of the elastic modulus compared to the aluminum alloy base.