Tribological properties of heterophases aluminium cast composites containg chromium and titanium carbides
Anna Dolata-Grosz*, Jakub Wieczorek** *Politechnika Śląska, Wydział Inżynierii Materiałowej i Metalurgii, Katedra Technologii Stopów Metali i Kompozytów, ul. Krasińskiego 8, 40-019 Katowice **Politechnika Śląska, Wydział Inżynierii Materiałowej i Metalurgii, Zakład Kompozytów i Metalurgii Proszków, ul. Krasińskiego 8, 40-019 Katowice
Quarterly No. 3, 2006 pages 26-32
DOI:
keywords: AMCs, heterophase reinforcement, casting methods, tribological properties
abstract The application of heterophase reinforcement is a solution which enables the broadening of the possibilities of designing the tribological properties of friction couples. The appropriate choice of components such as matrix and reinforcing phases allows us to limit the wear of the elements of frictional couple and to gain the stability of friction coefficient. This article presents the research results on tribological properties (friction coefficient, wear) of the frictional couple cast iron-composite. The subject of that research was heterophase composites containing chromium carbides (Cr3C2) and titanium carbides (TiC). The aluminium-magnesium alloy (AlMg10) was used as a matrix of the produced composites. The result of self-propagating high-temperature synthesis (SHS) were the reinforcing phases such as mixture of composite powder like NiCr-Cr3C2-TiC used in technological process as a consolidation carrier. The structure and phase composition of the composite powder used in modification of aluminium alloy is shown in Figure 1. The method of mechanical stirring of composite suspended matter conducted in 720°C was used to produce AlMg10/NiCr-Cr3C2-TiC composite ingot being a semi-finished product in the applied technological process. The obtained castings were characterized by complex phase structure of different morphology and chemical composition (Fig. 3). The sleeves that were formed using the centrifugal casting method, with vertical axis, were used for further tribological research. Tribological investigations of cast iron - composite couple were carried out under technically dry friction on a T-01 pin-on-disk tester. The centrifugal cast composite constituted the disc; the friction partner was the cast iron pin. The device’s diagram used in tribological examinations is presented in Figure 2. The process of wear and changes of friction coefficient in the path function is presented in histograms as an absolute mass decrement of composite and the cooperating cast iron respectively (Figs. 4, 6, 8). The created composites were measured with Brinell hardness method and the results were presented in the form of diagram, shown in Figure 9. The results obtained during tribological examinations allow us to state that the amount of used reinforcement does not influence the value of friction coefficient composite - cast iron couple. Volume fraction of the applied reinforcement influences the level of friction partner wear, that is the cast iron. All the conducted tests of the centrifugal casting method of composite suspended matters proved to be correct; it also enables creating layered castings used in tribological conditions.