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Structure and Properties of Mg-Cu-(Y,Ca) Bulk Metallic Glasses

Babilas R., Cesarz-Andraczke K., Nowosielski R.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 4

2645--2650

EN

The work presents preparation methods, structure characterization and mechanical properties analysis of Mg-based bulk metallic glasses in as-cast state and after crystallization process. The studies were performed on Mg60Cu30Y10 and Mg37Cu36Ca27 glassy alloys in the form of plates and rods. The X-ray diffraction investigations revealed that the tested samples with different thicknesses and shapes were amorphous. The characteristics of the fractured surfaces showed mixed fractures with the “river” and “mirror” patterns, which are characteristic for the glassy materials and some “smooth” areas. The samples of Mg37Cu36Ca27 alloy presented a two-stage crystallization process, but addition of Y caused a single stage crystallization behavior. Qualitative phase analysis from the X-ray data of examined alloys annealed at 473 K enabled the identification of Mg, Mg2Cu, Cu2Mg and CaCu crystalline phases. The changes of compressive strength as a function of annealing temperature for studied rods were stated. The best mechanical properties including microhardness and compressive strength were obtained for the alloy with the addition of Y in as-cast state.

PL

W pracy przedstawiono wyniki badań struktury i wybranych własności masywnych szkieł metalicznych na osnowie magnezu. Badania przeprowadzono na próbkach w stanie wyjściowym oraz po procesie wygrzewania. Do badań wybrano dwa trójskładnikowe stopy magnezu z dodatkiem itru lub wapnia o następującym składzie chemicznym:Mg60Cu30Y10 oraz Mg37Cu36Ca27. Badania rentgenowskie potwierdziły, że analizowane próbki w postaci płytek i prętów posiadają strukturę amorficzną. Obserwacje mikroskopowe wybranych obszarów powierzchni przełomów płytek i prętów pozwoliły na wyodrębnienie stref o morfologii przełomów „gładkich” i „łuskowych”. Analiza procesu krystalizacji wykazała występowanie pojedynczego etapu krystalizacji dla szkła metalicznego Mg60Cu30Y10 związanego z wydzielaniem się fazy Mg2Cu oraz dwuetapowego procesu krystalizacji dla stopu Mg37Cu36Ca27, w którym zidentyfikowano fazę Cu2Mg i CaCu. Największą wytrzymałość na ściskanie oraz mikrotwardość uzyskano dla próbek szkła metalicznego z dodatkiem itru w stanie bezpośrednio po odlaniu.

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Wpływ procesów biochemicznych i substancji humusowych na stężenie związków wapnia i magnezu w wodach

Kolanek A., Kowalski T.

Ochrona Środowiska

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2002

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nr 1

9-12

EN

The results of laboratory tests showed that biochemical oxidation, as well as concomitant biocoagulation phenomena, brought about a change of the calcium and magnesium concentration in the water. This led to the establishment of a new calcium-magnesium equilibrium in the humic substances, which were present in the water. As a result, calcium concentration in the investigated water samples underwent some variations (but not substantial changes). The said processes exerted an indirect effect on the concentration of magnesium. When following addition of a sewage portion the value of the Ca/Mg molar ratio fell below that of the Ca-Mg equilibrium in the humic substances, the concentration of magnesium decreased in the course of biochemical degradation. When the Ca/Mg ratio value exceeded the Ca-Mg equilibrium value, magnesium concentration increased. The decrement or increment of magnesium was BOD5-dependent and averaged 0.045 val/gO2. Statistical analysis of the relationship between calcium and magnesium concentration variations for 8 rivers and 24 cross-sections substantiated the results of laboratory tests. Over 92% of instances showed a positive annual [Mg] = f([Ca]/[Mg]) relation with a coefficient of determination greater than 0.6. A positive annual [Ca] = f([Ca]/[Mg]) relation was detected in 6% of instances.

3

Wpływ procesów biochemicznych na stężenia związków wapnia i magnezu w wodach

Kolanek A., Kowalski T.

Ochrona Środowiska

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2001

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nr 1

17-21

EN

Biochemical oxidation and concomitant biocoagulation phenomena were found to produce loss of calcium and magnesium cations in treated water, thus contributing to the stabilization Ca-Mg equilibrium in the double layer of the humus complex. As a result, calcium concentration in the investigated water varied only negligibly. The effect of biochemical processes on magnesium concentration was an indirect one. If after sewage addition the Ca/Mg molar ratio value stabilized below the Ca-Mg equilibrium in the humus complex, magnesium concentration decreased in the course of the biochemical degradation process. If the said ratio value was greater than the equilibrium value, magnesium concentration increased.

4

Zawartość związków wapnia i magnezu w wybranych wodach i osadach ściekowych Górnego Śląska

Bodzek D., Janoszka B., Tyrpień K., Wielkoszyński T.

Ochrona Środowiska

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1998

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nr 4

18-19

EN

Magnesium and calcium ion concentrations were determined in drinking water and wastewater sludge samples coming from the industrialized Upper Silesian Region and ( for comparative purposes ) from different non- industrialized bockground areas.Mg2+ Ca2+ concentrations in water samples were measured by spectrophotometry ( Mg2+ concentration in the reaction with the Mann and Yoe agent,and Ca2+ concentration in reaction with metalphthalein). In wastewater sludge, Mg2+ and Ca2+ content was determined by AAS.The concentration of Mg2+ in the water samples was generally below the concentrations of both the ions were noticeably high,thus making the investgated sludge snitable for agricultural uses,provided that the concentration of heavy metals is within the range of permissible values.