The precipitation process in Cu-30%Ni-1∼3%Al alloys during aging at 773 or 873 K after water quenching from 1323 K, and the characteristics of the nodule formed by the grain boundary reaction were investigated by means of optical and electron microscopy, hardness measurement and X-ray diffraction analysis.
When the specimens were aged at 873 K, the hardness measured at room temperature increased monotonously with the progress of aging. But hardening occurred in two stages during aging at 773 K . The lines of θ phase and the side-bands were observed in X-ray diffraction patterns from the early stage of aging. In the transmission electron micrographs, the modulated structure was observed at the early stage of aging. The mode of precipitation in the alloys was of the discontinuous type: α super-saturated solid solution→modurated structure→equilibrium α phase+equilibrium θ phase within the composition range from (Ni_0.67Cu_0.33)₃Al to (Ni_0.85Cu_0.15)₃Al.
Fine structure inside the nodule grew gradually during aging, and a granular θ phase was observed at the later stage of aging. The hardness inside the nodule changed with the growth of the fine structure.

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The process of atmospheric corrosion of the alloy MgIn has been investigated by means of reflection high energy electron diffraction, scanning electron microscopy, electron probe microanalysis and other techniques. The alloy surface in the as-polished state has a metallic luster but is already covered with a thin composite film consisting of magnesium oxide and isolated indium. When exposed to an atmosphere of high humidity, it is corroded forming a number of pits which are filled with corrosion products. Corrosion proceeds continuously until the alloy is changed into black, brittle products consisting of magnesium hydroxide and isolated indium metal. The latter then appears on the surface of the products in the form of whiskers and massive extrusions.

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The electrophoretic behaviours of chloro-complexes of Co(II), Cu(II), Fe(III), and Ni(II) in aqueous solutions of hydrochloric acid (1 to 10 N) were studied in the temperature range from 3 to 82°C.
At intermediate hydrochloric acid concentrations, the zones of Co(II), Cu(II), and Fe(III) migrate towards the cathode when the temperature is low, while with an increase in temperature the zones are reversed in their direction and migrate towards the anode. On the other hand, the zones of Ni(II) always migrate towards the cathode at all the temperatures and hydrochloric acid concentrations studied. For the Co(II), Cu(II), and Fe(III) zones, the hydrochloric acid concentration ranges where the direction reversion appeared with increasing temperature were determined.
The results can be explained in terms of a predominant formation of higher chloro-complexes at higher temperatures.

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The course of the phase transformations upon cooling of a multicomponent Cu–10Al–3Fe–2Mn aluminium bronze has been followed by means of thermal analysis, dilatometry, X-ray diffraction, X-ray microanalysis, optical metallography as well as by electrical resistivity and hardness measurements. The continuous cooling transformation (CCT) phase diagram of the bronze has been constructed and the effect of the cooling rate on the phase composition, microstructure and various physical properties of the alloy has been determined.

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