The aim of this thesis was to improve the properties of pressed and sintered aluminium powder alloys. This improvement was to be achieved using two methods. The first method involved the selection of an alloy system using binary aluminium phase diagrams and a knowledge of the phase diagram characteristics of ideal sintering systems. The second approach involved the judicious use of selected trace element additions to modify the sintering characteristics of aluminium and its alloys. A trace amount of magnesium was found to be critical to the sintering of aluminium powder due to its disrupting effect on the tenacious oxide layer covering the powder particles. The critical amount of Mg required to optimise both density and mechanical properties is dependent on the specific volume of oxide and the therefore particle size. The optimum concentration is 0.1-1.0wt% Mg. The Al-Sn phase diagram exhibits many of the characteristics of an ideal sintering system. Unsurprisingly, Sn was found to be an extremely efficient sintering aid, but only in the presence of Mg. Near full density parts were produced using an Al-8Sn-0.15Mg alloy in short sintering times (30 minutes). Additionally, as-sintered ductilities exceeding 20% were achieved using an Al-2Sn-0.15Mg alloy. Alloys based on the Al-Sn-Mg system lend themselves to sintering without compaction and therefore freeformed Al-Sn-Mg alloys have been produced and sintered to near full density from a starting density of ~50%. Trace amounts of Sn (Pb, In, Bi, or Sb) enhance the sintering response of an Al-4Cu-0.15Mg alloy via a vacancy binding mechanism. A similar mechanism suppresses natural ageing and stimulates artificial ageing when trace amounts of Sn are added to this alloy. A Sn-modified 2XXX series alloy has also been produced with mechanical properties nearly 20% above current commercial alloys. Along with the addition of 0.1wt%Sn, this improvement required an alteration to the solution treatment cycle which allowed the use of a higher sintering temperature without the formation of large amounts of boundary phase.

Al93Fe3Cr2Nb2 (at.%) nanoquasicrystalline alloys have been shown to have the potential to push the applications of aluminium alloys to more elevated temperatures, by maintaining a high strength. They also have more thermally stable microstructures than previous nanoquasicrystalline alloys from similar systems (the most studied of which is Al93Fe3Cr2Ti2 (at.%)). Al93Fe3Cr2Nb2 (at.%) alloys have never previously been produced in samples on a scale larger than melt-spun ribbon. This study examines the production parameters of bulk nanoquasicrystalline Al-Fe-Cr-Nb alloys. Firstly an attempt was made to reduce the melting temperatures of thermally stable nanoquasicrystalline alloys through additional alloying. The melting processes of binary, ternary, quaternary and quinary nanoquasicrystalline alloys was analysed though DTA, with endothermic reactions up to 1034oC observed. Rapidly solidified Al-Fe-Cr-Nb alloys were then produced in kilogram quantities through gas atomisation at an industrial scale. The smallest atomised powder particles contained fine scale microstructures consisting of nano-scale quasicrystals embedded in an aluminium matrix. As the cooling rate of the powder particles decreased new phases, including the theta phase (Al13(Fe,Cr)2-4) and Al3Nb were produced. 0-25μm, 25-50μm and 50-75μm (diameter) size fractions of atomised powder were each consolidated through extrusion to produce nanoquasicrystalline Al-Fe-Cr-Nb bars. Composite bars of the nanoquasicrystalline alloy mixed with 10(vol.)% and 20(vol.)% pure aluminium were also produced. The consolidation of the nanoquasicrystalline atomised powders through extrusion led to precipitation of intermetallics including (Al13(Fe,Cr)2-4) and Al3Nb, particularly in the smallest powder size fractions with the most metastable microstructures. Finally the effects of the atomisation and extrusion conditions on the microstructure and its mechanical properties were studied. Improved strength, coupled with reduced ductility was observed with decreases in the elemental aluminium composition of the Al-Fe-Cr-Nb bars and the powder size fraction they were produced from. There was however improvements in toughness of the extruded composite bars, over the nanoquasicrystalline alloy bars.

The subject of this thesis is to verify effect of aluminium powder in ground refractory coatin, which is intended for casting od steel castings to organic bonded moulds. The pre-sence of aluminium powder in ground coating was expertised on term of coating in itself - that means immunity to heat shock, penetration etc., and in term of influence on formation of surface defects etc. Outputs of this thesis are: setting of optimum amount of aluminium powder in ground coating and statistically verified analysis of effects of modified coating in term of creation of defects

The work deals with the development of a new thermal insulation material that contains a secondary raw materials or waste. It is an insulating material with the requirement of resistance to high temperatures - 200 ° C and 500 ° C. Type of material is determined by the way of reducing density - direct and indirect. Direct is achieved by adding lightweight aggregates, indirect is achieved by gas evolution through chemical reaction and the subsequent incorporation of gas into the structure of the material. This thesis is part of the MPO TIP č. FR-TI 2/340 project.