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.

Paper present a thermal analysis of laser heating and remelting of EN AC-48000 (EN AC-AlSi12CuNiMg) cast alloy used mainly for

casting pistons of internal combustion engines. Laser optics were arranged such that the impingement spot size on the material was a

circular with beam radius rb changes from 7 to 1500 m. The laser surface remelting was performed under argon flow. The resulting

temperature distribution, cooling rate distribution, temperature gradients and the depth of remelting are related to the laser power density

and scanning velocity. The formation of microstructure during solidification after laser surface remelting of tested alloy was explained.

Laser treatment of alloy tests were perform by changing the three parameters: the power of the laser beam, radius and crystallization rate.

The laser surface remelting needs the selection such selection of the parameters, which leads to a significant disintegration of the structure.

This method is able to increase surface hardness, for example in layered castings used for pistons in automotive engines.

This research describes effects of Si addition on microstructure and mechanical properties of the Al-Cr based alloys prepared manufactured using gas atomization and SPS (Spark Plasma Sintering) processes. The Al-Cr-Si bulks with high Cr and Si content were produced successfully using SPS sintering process without crack and obtained fully dense specimens close to nearly 100% T. D. (Theoretical Density). Microstructure of the as-atomized Al-Cr-Si alloys with high contents of Cr and Si was composed multi-phases with hard and thermally stable such as Al13Cr4Si4, AlCrSi, Al8Cr5 and Cr3Si intermetallic compounds. The average hardness values were 703 Hv for S5, 698 Hv for S10 and 824 Hv for S20 alloy. Enhancement of hardness value was resulted from the formation of the multi-intermetallic compound with hard and thermally stable and fine microstructure by the addition of high Cr and Si using rapid solidification and SPS process.

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.

Particles of the Fe-Al type (less than 50 µm in diameter) were sprayed onto the 045 steel substrate by means of the detonation method. The TEM, SAED and EDX analyses revealed that the Fe-Al particles have been partially melted in the experiment of coating formation. Particle undergone melting even within about 80% of its volume. Therefore, solidification of the melted part of particles was expected. Solidification differed significantly due to a large range of chemical composition of applied particles (from 15 at.% Al up to 63 at.% Al). A single particle containing 63 at.% Al was subjected to the detailed analysis, only. The TEM / SAED techniques revealed in the solidified part of particle three sub-layers: an amorphous phase, A ε , periodically situated FeAl + Fe2Al5 phases, and a non-equilibrium phase, Nε . A hypothesis dealing with the inter-metallic phases formation in such a single particle of the nominal composition 0 N = 0.63 is presented. At first, the solid / liquid system is treated as an interconnection: substrate liquid nonmelted particle part / / . Therefore, it is suggested that the solidification occurs simultaneously in two directions: towards a substrate and towards a non-melted part of particle. The solidification mechanism is referred to the Fe-Al meta-stable phase diagram. It is shown that the melted part of particle solidifies rapidly according to the phase diagram of meta-stable equilibrium and at a significant deviation from the thermodynamic equilibrium.