Maja Vončina

Effect of Ce on morphology of α(Al)–Al2Cu eutectic in Al–Si–Cu alloy

Abstract The effect of Ce addition on the morphology of the α(Al)–Al 2 Cu eutectic in Al–Si–Cu alloy was investigated using thermal analysis, light microscopy, scanning electron microscopy, focused ion beam and energy dispersive analysis. The results show that the eutectic α(Al)–Al 2 Cu forms within small space between dendrites, silicon and AlSiFeMn plates. Eutectic Al 2 Cu is not lamellar but degenerated. However, Al 2 Cu in Ce-modified alloys is more compact. Ce partially dissolves in Al 2 Cu, which is a viable reason for the formation of coarser Al 2 Cu. The addition of Ce also increases the microhardness of the α(Al)–Al 2 Cu eutectic by almost 10% compared with the basic Al–Si–Cu alloy.

Development of Innovative Al–Si–Mn–Mg Alloys with High Mechanical Properties

In modern practice standard materials do not satisfy the rigorous requirements for applications. Paper represents thermodynamic modeling of innovative aluminium alloys with better mechanical properties for high temperature applications. Using different combinations of alloying elements in specific temperature regions the information of which specific phase (solid solution, intermetallic compound) is formed. Alloys systems Al–X–Y (X = Si, Mn, Mg; Y = Zr, Mo) were investigated using thermodynamic equilibrium calculations (ThermoCalc), thermal analysis, and optical and scanning electron microscopy, in order to analyze the corresponding properties. Determination of chemical composition and types of phases, amount of phase and study of equilibrium and non-equilibrium processes, the characteristic solidification temperatures and mechanical properties for laboratory and industrial aluminium alloys was done.

Thermodynamic characterization of aluminium corner of Al–Cu system with various Nd additions

The effect of various neodymium additions on the characteristic solidification temperatures and on the microstructure development of the laboratory-prepared binary alloy AlCu5.5 was investigated. The aluminium corner of ternary system Al–Cu with various Nd additions was investigated using thermal analysis, differential scanning calorimetry and optical and scanning electron microscopy. The presence of Nd phases was confirmed using X-ray diffractometer. Microhardness of α-Al in AlCu5.5 alloy containing various Nd additions was analysed. The results show that the addition of neodymium raises eutectic (α-Al + Al2Cu) solidification temperature and solidus temperature, which leads to a narrower solidification interval. It was also confirmed that Nd formed two binary eutectics (α-Al + Al2Cu(Nd)) and (α-Al + Al8Cu4Nd). The addition of Nd also caused the increase in microhardness of α-Al phase.