Inclusions in primary aluminium were analysed with an electron-probe microanalyser and a high-resolution Auger electron spectrometer. In multiphase eutectic and complex inclusions the presence of ...calcium, magnesium, iron, copper, molybdenum and aluminium was detected. Prior to Auger analysis, sufficient ion etching is necessary for the elimination of oxides from the surface. The complex inclusions, with calcium content, reacted with water which demanded the choice of a suitable technique for the preparation of metallographic samples.
This work deals with the influence of TiB
2 particles already present, and added in the form of Al–5Ti–1B grain refiner, on the effectiveness of Al–3Ti–0.15C grain refiner in an Al–Fe alloy. We found ...that Al–3Ti–0.15C grain refiner is ineffective in the case of the addition of both Al–5Ti–1B and Al–3Ti–0.15C grain refiners to an Al–Fe alloy. Despite the presence of TiB
2 particles in the Al–Fe alloy, Al–3Ti–0.15C grain refiner is, however, effective when added on its own to an Al–Fe alloy. The effectiveness and ineffectiveness of Al–3Ti–0.15C grain refiner with Al–Fe alloys were also confirmed by the presence of TiC particles and TiB
2 particles in the centres of the α-Al grains. Recalescence on solidification measured by in-situ thermal analysis can explain the effectiveness and ineffectiveness of Al–3Ti–0.15C grain refiner in Al–Fe alloys.
In our investigation of the AgCu25Zn20Cd20 soldering alloy, cadmium was partly or fully replaced by indium and tin due to its toxicity. The influence of this substitution on the fraction, morphology ...and distribution of the identified phases has been examined. Beside *aAg and *aCu the intermetallic phases of *b-AgCd(Zn), *b-CuSn and *d-CuIn have been established after annealing of the alloys at 500T for 300 hours by X-ray phase analysis. The presence of the *b-CuSn phase shows the influence of indium on the stability of that phase at lower temperatures. By microanalysis the distribution of metals in the present phases has been qualitatively determined. The influence of indium and tin on the liquidus and solidus temperatures is similar to that of the substitution of cadmium only by indium. Measured hardness of the cast alloys shows the favourable influence of the common substitution with indium and tin in comparison with substitution with one metal only.
In our investigation of the AgCu25Zn20Cd20 alloy, cadmium was partly or fully replaced by indium due to its toxicity. The influence of this substitution on the fraction, morphology and the ...distribution of the identified phases has been examined, and the indium distribution in the single phases was established. Melting intervals of several alloys have been determined and their hardness in the cast or in heat-treated state was measured. By means of X-ray diffraction (XRD) phase analysis the intermetallic phase of delta -CuIn has been already established in the alloy with 5 wt.% In. The hardness of the cast alloys was strongly increased and the technological procedures of their manufacture was reduced in the presence of that phase. With higher fraction of indium in the alloy the quantity of the ternary eutectic ( alpha sub Ag + alpha sub Cu + beta sub AgCd ) in the microstructure was decreasing, and the quantity of ternary mixed crystals alpha sub Ag increased up to 60 vol.%, while the quantity of alpha sub Cu remained fixed. By substitution of indium for cadmium, the melting point decrease to 586 deg C and a smaller solidification interval in the alloy of AgCu25Cd15Zn20In5 have been observed.
A comparison of performance of AlTi5B1 and AlTi3C0.15 grain refiners in commercial-purity aluminum AA 1080 at contents up to 10 g*kg-1 for AlTi5B1 and 16 g*kg-1 for AlTi3C0.15 grain refiner is ...studied in this work. The results show that AlTi5B1 grain refiner is much more effective in suppressing the growth of columnar grains at the same titanium content. AlTi5B1 grain refiner in comparison to AlTi3C0.15 grain refiner also shows smaller grain size at the same titanium content except at the highest one. It was observed that the effectiveness of AlTi5B1 grain refiner decreases at the content above 4 g kg-1. Similar behaviour was not found for AlTi3C0.15 grain refiner. The differences in the behaviour of the both refiners at the high refiner content can be explained by the differences in the mechanism of the grain refinement.
The changeover to cast Al strip for foil production has been defined by the management of Impol as the key part of its strategy for the plant's development and the restructuring of roll-casting ...technology. In comparison with hot-rolled strip, continuous cast strip is a cost-effective raw material for foil production, but different in terms of microstructure, phase composition, formability and other technological characteristics. Due to the very rapid solidification of molten metal in continuous thin strip, the microstructure consists of a strongly supersaturated aluminium solid solution and an increased fraction of fine particles of intermetallic phases, precipitated in Al crystal grains. This has a negative effect on cast-strip formability, and moreover, the cast strip's surface is oxidized and contaminated with graphite. For the purpose of producing strip from technical aluminium (group AA 1xxx) and alloys of the Al-Fe type (group AA8xxx) it was necessary to change the casting parameters as well as the parameters for further strip processing, which differ from conventional roll-casting procedures. Continuous cast strip is primarily intended for insulation, converter and household foils of different widths. The principal foil characteristics, prescribed by EN standards, are the mechanical characteristics, surface quality, porosity and the thermostability. The research work was focused on achieving the listed characteristics by changing the alloy composition and the conditions of transformation of continuous cast strip into foil. A suitable thermomechanical treatment changes the distribution of alloy elements in the existing microstructural phases and thereby also their effect on static recrystallisation, thereby affecting the surface quality and the mechanical characteristics of the foil. In this study the optimum composition and the process parameters of continuous casting that make it possible to use the strip as raw material for producing sheets and insulation, converter and household foils of standard quality are presented.
