In the aluminium alloy family, Al-Zn materials with non-standard chemical composition containing Mg and Cu are a new group

of alloys, mainly owing to their high strength properties. Proper choice of alloying elements, and of the method of molten metal treatment

and casting enable further shaping of the properties. One of the modern methods to produce materials with submicron structure is a method

of Rapid Solidification. The ribbon cast in a melt spinning device is an intermediate product for further plastic working. Using the

technique of Rapid Solidification it is not possible to directly produce a solid structural material of the required shape and length.

Therefore, the ribbon of an ultrafine grain or nanometric structure must be subjected to the operations of fragmentation, compaction,

consolidation and hot extrusion.

In this article the authors focussed their attention on the technological aspect of the above mentioned process and described successive

stages of the fabrication of an AlZn9Mg2.5Cu1.8 alloy of ultrafine grain structure designated for further plastic working, which enables

making extruded rods or elements shaped by the die forging technology. Studies described in the article were performed under variable

parameters determined experimentally in the course of the alloy manufacturing process, including casting by RS and subsequent

fragmentation.

Contemporary materials engineering requires the use of materials characterised by high mechanical properties, as these precisely

properties determine the choice of material for parts of machinery and equipment. Owing to these properties it is possible to reduce

the weight and, consequently, the consumption of both material and energy. Trying to meet these expectations, the designers are

increasingly looking for solutions in the application of magnesium alloys as materials offering a very beneficial strength-to-weight ratio.

However, besides alloying elements, the properties are to a great extent shaped by the solidification conditions and related structure.

The process of structure formation depends on the choice of casting method forced by the specific properties of casting or by the specific

intended use of final product. The article presents a comparison of AZ91 magnesium alloys processed by different casting technologies.

A short characteristic was offered for materials processed by the traditional semi-continuous casting process, which uses the solidification

rates comprised in a range of 5 - 20⁰C/s, and for materials made in the process of Rapid Solidification, where the solidification rate can

reach 106 ⁰C/s. As a result of the casting process, a feedstock in the form of billets and thin strips was obtained and was subjected next

to the process of plastic forming. The article presents the results of structural analysis of the final product. The mechanical properties

of the ø7 mm extruded rods were also evaluated and compared.

The effect of plastic deformation process on the dissolution rate of biocompatible Mg alloys was investigated. Two biocompatible MgLi1Ca0,2Zn1 and MgLi1Ca1Zn1 alloys were selected for the study. The alloys were deformed on a 100T press at a temperature of 350°C by conventional extrusion and by the equal channel angular extrusion process (ECAE). The grain size analysis showed a high degree of the grain refinement from approximately 110 mm in the initial state to 2.8 mm after the 3rd pass of the ECAE process. Compared to as-cast state, the degree of strengthening has increased after plastic forming. The results of biodegradation tests have shown a significant increase in corrosion rate after both conventional extrusion and ECAE, although after subsequent ECAE passes, this rate was observed to slightly decrease in the MgLi1Ca1Zn1 alloy. Based on the results of macro- and microstructure examinations, the corrosion progress in samples after the extrusion process was described.

The article presents research aimed at determining the effect of adding rare earth elements to near-eutectic Al-Si and Al-Si-Ni alloys on the microstructure and mechanical properties of the obtained products. Material for the research was prepared using a melt spinner – a device used for rapid crystallization, casting thin ribbons, which were then subjected in subsequent stages to fragmentation, consolidation and plastic working. The ribbons and extruded rods cast were described in terms of their structure and their strength properties were determined at different measurement temperatures. It was shown that the lightweight materials produced from aluminium alloys using the rapid solidification process have an ultra-fine structure and good strength properties.

Analysis under a microscope confirmed that the addition of rare earth alloys Al-Si and Al-Si-Ni causes fragmentation of the microstructure in the tapes produced. The presence of rare earth elements in the alloys tested has an impact on the type and the morphology of the particles of the microstructure’s individual components. In addition to the change in particle morphology, the phenomenon of the separation of numerous nanometric particles of intermetallic phases containing rare earth elements was also observed. The change in microstructure caused by the addition of rare earth elements in the form of a mischmetal increases the mechanical properties.