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Study of lead-free solders liquidus and solidus temperatures by means of DTA-method

Docekalova S., Smetana B., Drapala J., Perinova K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

2007

Vol. 321, z. 89

99-99

The thermal analysis is very effective tool in the study of thermophysical and thermodynamical properties (e.g. temperatures of phase transformations, latent heats -enthalpies of phase transformations,...) among others, metallic systems. One of the most widespread methods of thermal analysis used for the description of metallic systems behaviour is the Differential Thermal Analysis - DTA. The aim of our work was study of characteristic phase transformation temperatures (temperatures of solidus - T$ and liquidus - TL) of lead-free solders on the base of tin. In total 22 alloys with different ratios of individual elements Ag, Cu, In, Sb, Bi, Zn and Sn were prepared experimentally. In addition, six alloys of lead-free solders produced commercially (Kovohute Pf ibram) were used and the Pb-Sn solder served as a comparative alloy. The alloys were prepared by smelting of input metals in the graphite crucible followed by casting into graphite boat. Temperatures of solidus and liquidus were obtained with use of experimental laboratory system SET ARAM SETSYS 18TM TG/DTA/TMA. Samples of solders in the form of small disordered pieces (size up to approx. 3 mm and max. mass 0.2 g) were during measurement heated and cooled in a controlled manner at the rate of 4°C/min. The A12O3 crucibles were used for measurement. Argon (purity > 99.999999%) was used for washing of the inert space of oven before each analysis (flow time approx. 15 min), then evacuation followed and again filling up with argon. During analysis the constant dynamical atmosphere was kept in the oven space (flow rate of argon was 2 1/h). Differences between experimentally determined temperatures of Ts, TL acquired during controlled heating and cooling were observed. These differences could be influenced not only by undercooling, but also by dynamics of measuring process.

Zastosowanie sieci neuronowych do modelowania temperatury solidus podeutektycznych stopów Al-Si-Cu

Dobrzański L. A., Maniara R., Sokolowski J. H., Kierkus W. T.

Archiwum Odlewnictwa

2006

R. 6, nr 22

606-613

W pracy zaprezentowano metodę obliczania temperatury solidus dla podeutektycznych stopów Al-Si-Cu chłodzonych z różnymi szybkościami chłodzenia za pomocą sieci neuronowych. Dla sprawdzenia poprawności modelu wyznaczającego temperaturę solidus w funkcji składu chemicznego i prędkości chłodzenia wykonano eksperyment laboratoryjny. Wyniki przeprowadzonego eksperymentu laboratoryjnego potwierdzają poprawności opracowanego modelu.

This article presents the application of neural networks for prediction of the solidus temperature of various hypoeutectic Al-Si-Cu casting alloys cooled with different cooling rate. Knowledge of solidus temperature allows the prediction of a variety of metallurgical characteristics i.e. melt treatment, casting temperature. The paper presents computational algorithm calculation of solidus temperature and influence of alloying elements on solidus temperature. The accuracy of the calculated solidus temperature was comprised with the values measured by the thermalanalysis.