Mg-1.6Gd binary alloy was subjected to uniaxial warm rolling at a unidirectional and cross-sectional with a reduction ratio of 95% in order to observe the relationship between its microstructural changes to the degradation behavior. The warm rolling was performed at a temperature range of its recrystallization temperature, which were 400°C and 560°C, and a feed rate of 10 mm/min. Degradation behaviors of Mg-1.6Gd binary alloy was evaluated by means of potentiodynamic polarization and hydrogen evolution test in modified Kokubo’s SBF solution at temperature of 37 ± 1ºC. The lowest corrosion rate of 0.126 mm/year derived from potentiodynamic polarization test was showed by unidirectional-rolled specimen at temperature of 560 °C. Hydrogen evolution test results showed the lowest hydrogen gas formed during 24 hours of immersion was found on unidirectional-rolled specimen at temperature of 560°C with a rate of 0.268 cc/cm2/hours. While cross rolled specimens showed a high corrosion and hydrogen evolution rate of 20 mm/year and 0.28 cc/cm2/hours.

The paper presents research of metallic glass based on a Mg72Zn24Ca4 alloy. Metallic glass was prepared using induction melting and further injection on a spinning copper wheel. The X-ray diffractometer and differential scanning calorimeter (DSC) were used to investigate the phase transformation of the amorphous ribbon. The heat released in the crystallization process, during isothermal annealing, based on the differential scanning calorimeter investigation, was determined to be 166.18 Jg-1. The effect of isothermal annealing temperature on the kinetics of the amorphous alloy crystallization process using differential scanning calorimeter was investigated. For this purpose, two isothermal annealing temperatures were selected. The incubation time decreases as the temperature of the isothermal annealing increases from 300 to 252 seconds. The same relationship is visible in the case of duration of the phase transformation, which also decreases as the temperature of the isothermal annealing increases from 360 to 228 seconds. The obtained results show a significant influence of isothermal annealing temperature on the degree of phase transformation.

Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an

aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and

the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the

layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al,

Al3Mg2, Mg17Al12 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670o

C and 310 o

; variant 2 – 680o

C and 310o

C, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher

temperatures of the melt (685o

C) and the mould (325o

C) resulted in deep penetration of aluminium into the magnesium substrate. Areas

enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from

187-256 HV0.1.

High-power terahertz sources operating at room-temperature are promising for many applications such as explosive materials detection, non-invasive medical imaging, and high speed telecommunication. Here we report the results of a simulation study, which shows the significantly improved performance of room-temperature terahertz quantum cascade lasers (THz QCLs) based on a ZnMgO/ZnO material system employing a 2-well design scheme with variable barrier heights and a delta-doped injector well. We found that by varying and optimizing constituent layer widths and doping level of the injector well, high power performance of THz QCLs can be achieved at room temperature: optical gain and radiation frequency is varied from 108 cm⁻¹ @ 2.18 THz to 300 cm⁻¹ @ 4.96 THz. These results show that among II–VI compounds the ZnMgO/ZnO material system is optimally suited for high-performance room-temperature THz QCLs.

The study was conducted in the area of the impact of sulfur mine in Jeziórko. The aim of the study was to assess changes in pH, cation exchange capacity and content of available phosphorus, potassium and magnesium after 6 years of conducting remediation. In the experiment (plots with an area of 15 m2) degraded soil was rehabilitating by post-floating lime and compost from sewage sludge, sewage sludge and ash from combined heat and power (CHP). Composts at a dose of dry matter 180 t · ha-1 (6%), were determined in accordance with Minister of the Environment Regulation from 2001, applied the following options: control (only native soil limed), compost from municipal sewage sludge, sewage sludge compost (80%) and ash (20%), compost from sewage sludge (70%) and ash (30%). The reclaimed plots were sown with mixture of rehabilitation grass. Single de-acidification, land fertilization and a further 6-year extensive (without fertilization) use had a different influence on the properties of the native soilless substratum. Irrespective of the reclamation manner, after six years land use in the upper layers, observed increase in the average content of available phosphorus, available potassium content does not changed significantly but recorded a tenfold decrease in the content of available magnesium.

In this study, solidification/stabilization (S/S) of electric arc furnace dust (EAFD) which is generated during the production of steel from scrap metals and classified as hazardous waste were investigated by using different ratios of cement and low grade MgO (LG MgO) as binding agents. Type I PC 42.5 R portland cement and LG MgO which contains 70–80% MgO were used. S/S blocks that contain different ratios of binding agents which have 1/0.5 – 1/1 – 1/2 – 1/3 – 1/4 – 1/5 cement/LG MgO ratio and S/S blocks which contain only cement and no LG MgO agents were prepared. These blocks, which contain 3 different waste ratios according to weight, 20%, 30% and 40% respectively, were produced and exposed to 28-day water purification. At the end of the purification process, S/S blocks were extracted using TCLP (Toxicity Characteristic Leaching Procedure) tests in order to determine the leaching behavior of Zn, Pb, and Cd in S/S blocks. By the end of this study, it was concluded that the recovery of EAFD is possible and applicable by immobilization. The findings of the study concluded that environmental performances or structural properties of blocks contain 30% waste by weight are suitable. This method is a proper one for recovering and treatment of EAFD with mixture of cement and LG MgO.

The results of activity studies of four catalysts in methanol synthesis have been presented. A standard industrial catalyst TMC-3/1 was compared with two methanol catalysts promoted by the addition of magnesium and one promoted by zirconium. The kinetic analysis of the experimental results shows that the Cu/Zn/Al/Mg/1 catalyst was the least active. Although TMC-3/1 and Cu/Zn/Al/Mg/2 catalysts were characterised by a higher activity, the most active catalyst system was Cu/Zn/Al/Zr. The activity calculated for zirconium doped catalyst under operating conditions was approximately 30% higher that of TMC-3/1catalyst. The experimental data were used to identify the rate equations of two types - one purely empirical power rate equation and the other one - the Vanden Bussche & Froment kinetic model of methanol synthesis. The Cu/ZnO/Al2O3 catalyst modified with zirconium has the highest application potential in methanol synthesis.

Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and 6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Raman microscopy in the composites microstructure.

Experimental Mg-Al-RE type magnesium alloys for high-pressure die-casting are presented. Alloys based on the commercial AM50

magnesium alloy with 1, 3 and 5 mass % of rare earth elements were fabricated in a foundry and cast in cold chamber die-casting

machines. The obtained experimental casts have good quality surfaces and microstructure consisting of an α(Mg)-phase, Al11RE3,

Al10RE2Mn7 intermetallic compound and small amount of α+γ eutectic and Al2RE phases.

To the main advantages of magnesium alloys belongs their low density, and just because of such property the alloys are used in aviation and rocket structures, and in all other applications, where mass of products have significant importance for conditions of their operation. To additional advantages of the magnesium alloys belongs good corrosion resistance, par with or even surpassing aluminum alloys. Magnesium is the lightest of all the engineering metals, having a density of 1.74 g/cm3 . It is 35% lighter than aluminum (2.7 g/cm3 ) and over four times lighter than steel (7.86 g/cm3 ). The Mg-Li alloys belong to a light-weight metallic structural materials having mass density of 1.35-1.65 g/cm3 , what means they are two times lighter than aluminum alloys. Such value of mass density means that density of these alloys is comparable with density of plastics used as structural materials, and therefore Mg–Li alloys belong to the lightest of all metal alloys. In the present paper are discussed melting and crystallization processes of ultra-light weight MgLi12,5 alloys recorded with use of ATND methods. Investigated magnesium alloy was produced in Krakow Foundry Research Institute on experimental stand to melting and casting of ultra-light weight alloys. Obtained test results in form of recorded curves from ATND methods have enabled determination of characteristic temperatures of phase transitions of the investigated alloy.

As-cast Mg-6Li-0.3Zn-0.6Y and Mg-6Li-1.2Zn-1.2Y (wt%) alloys were prepared and extruded at 260 oC with an extrusion ratio of 25. The microstructure and mechanical behavior of as-cast and extruded alloys are reported and discussed. The results show that Mg-6Li-1.2Zn- 1.2Y alloy is composed of α-Mg, β-Li, and W-Mg3Zn3Y2 phases while Mg-6Li-0.3Zn-0.6Y alloy contains α-Mg, β-Li, W-Mg3Zn3Y2 phase and X-Mg12ZnY. After hot extrusion, the microstructure of specimens is refined and the average grains size of extruded alloys is 15 μm. Dynamic recrystallization occurs during the extrusion, leading to grain refinement of test alloys. Both the strength and elongation of test alloys are improved by extrusion. The extruded Mg-6Li-0.3Zn-0.6Y alloy possesses an ultimate strength of 225 MPa with an elongation of 18% while the strength and elongation of Mg-6Li-1.2Zn-1.2Y alloy are 206 MPa and 28%, respectively. The X-phase in Mg-6Li-0.3Zn- 0.6Y is beneficial to the improvement of strength, but will lead to the decrease of ductility.

The AlMg10 aluminum alloy reinforced with SiC particles was subjected to friction stir processing (FSP). The composite was made by mechanical mixing and gravity casting. The mass fraction of SiC particles in the composite was about 10%. Evaluation of the effects of FSP treatment was performed by means of light microscopy, scanning electron microscopy, EDS and hardness measurement. It was found that the inhomogeneous distribution of SiC particles and their agglomeration, which were observable in the cast composite, were completely eliminated after FSP modification. The treatment was also accompanied by homogenisation of the material in the mixing zone as well as fragmentation of both the matrix grain of the composite and SiC particles. In the case of SiC particles, a change in their shape was also observed. In the as-cast composite, particles with dimensions from 30 to 60 µm and a sharp-edged polyhedral shape prevailed, while in the material subjected to friction treatment, particles with dimensions from 20 to 40 µm and a more equiangular shape prevailed. Pores and other material discontinuities occurring frequently in the as-cast composite were completely eliminated after friction modification. The recorded changes in the microstructure of the material were accompanied by an increase in the hardness of the composite by nearly 35%. The conducted investigations have shown that FSP modification of the AlMg10/SiC composite made by the casting method leads to favorable microstructural changes in the surface layer and may be an alternative solution to other methods and technologies used in surface engineering.

The grain boundary wetting phase transition in an industrial EZ33A cast alloy is studied. 12% of the grain boundaries are completely wetted at the temperature slightly higher than the eutectic transformation temperature (530°C). The fraction of wetted grain boundaries increases with temperature, reaches a maximum of 85% at 570°C, and does not change further until the alloy melts. In the as-cast state, the alloy has low ductile properties at the ambient temperature. The microstructure in the as-cast state corresponds to the wetting state at about 560°C, which indicates that the cooling rate in casting is almost equal to that in quenching. The volume and the surface fraction of the second phase and the hardness measured at the least wetted state of samples point to its good machinability. The wetting data are used to suggest a sequence of heat treatment and machining for processing EZ33A alloy parts.