CRYSTALLIZATION PROCESSES OF SOME AMORPHOUS ALLOYS

A series of Fe40Co40Zr8M2B10 (M=Nb, V, Cr, Ti, W, Al) alloys were prepared using melt-spinning. The thermal curve, structure and magnetic property of alloys are examined. Because of different negative heat of mixing between elements, only Fe40Co40Zr8M2B10 (M=Nb, V, Cr, Ti) alloys form amorphous structure. These amorphous alloys are annealed at different temperatures under vacuum conditions. The crystallization processes of four amorphous alloys are similar. In the primary stage of crystallization process, only α-Fe (Co) phase precipitates and Co element mainly distributes in the residual amorphous. For the four alloys after annealing at 550°C, there is a few differences in saturation magnetization (Ms) and coercivity (Hc) due to their different microstructures.

Examining the Possibilities of Analyzing the Solidification Process of Al-Si Alloy with the Infrared Camera

The paper presents the results of the crystallization process of silumin by the TDA thermographic method and the results of the cast microstructure obtained in the sampler ATD-10, that was cooling down in ambient air. The study was conducted for silumins AlSi8 and AlSi11 unmodified. The work demonstrated that the use of thermal imaging camera allows for the measurement and recording the solidification process of silumin. Thermal curve was registered with the infrared camera and derivative curve that was calculated on the base of thermal curve have both a very similar shape to adequate them TDA curves obtained from measurements using a thermocouple. Test results by TDA thermographic method enable quantitative analysis of the kinetics of the cooling and solidification process of hypo-and neareutectic silumins.

An Application for Infrared Camera in Analyzing of the Solidification Process of Al-Si Alloy

The paper presents the results of the crystallization process of silumin by the TDA thermographic method and the results of the cast microstructure obtained in the sampler TDA-10, that was cooling down in ambient air. The study was conducted for silumin AlSi11 unmodified. The work demonstrated that the use of thermal imaging camera allows for the measurement and recording the solidification process of silumin. Thermal curve was registered with the infrared camera and derivative curve that was calculated on the base of thermal curve have both a very similar shape to adequate them TDA curves obtained from measurements using a thermocouple. Test results by TDA thermographic method enable quantitative analysis of the kinetics of the cooling and solidification process of neareutectic silumin.

A Preliminary Discussion of the Polynomial Fits to the Thermal Curves of Solid-Solid Reactions, Carried Out in Bulk

Dozens of authors have obtained experimental thermal curves of solid-solid reactions, carried out in bulk. Different mathematical functions were used to obtain fits to the thermal curve data. Polynomials were found to give the best fits to the data. The data may be divided into three types on the basis of the shape of the curves, with one peak, with two peaks and with three peaks. In this preliminary report we present one fitted curve of each of the three types as specimen. The importance of the Thermal Curves is briefly pointed out. A detailed discussion of the large amount of the available data may be taken up later.

“Global Warming”: Myth or Reality?

The “Global Warming scenario” is a hypothesis derived from theoretical models, asserted but not proven. There are numerous inconsistencies between predictions and actual observed climatic facts. The “global” thermal curve has no real significance in climatic terms. Climatic change is not global, but regional: for example, in the North Atlantic aerological unit, the Western side is cooling while that of the Northeast is warming. The 1970s exhibit a fundamental climatic switch which is not “seen” by the models, but is associated with a gradual increase of violent perturbations and irregularity of weather, linked to a change in the general circulation mode (rapid mode).