Przemysław Snopiński

Structure and properties of aluminium–magnesium casting alloys after heat treatment

Since the forming of the microstructure depends on the specific of the casting method, which directly affects further mechanical and physical properties of the material, it is important to understand how to control the microstructure of the cast to understand changes that taking place during the crystallisation process. For estimating the metallurgical quality of the liquid metal before casting, the thermal-derivative analysis (TDA) is utilised. The TDA has been used for a long time, in both ferrous and non-ferrous industries casting. The Universal Metallurgical Simulator and Analyser (UMSA) platform is a rapid, sensitive and economical method of determining a full range of solidification features. The work focuses on the thermal analysis and heat treatment of aluminium alloys. The liquidus and solidus temperatures and dendrite coherency point (DCP) are then characterised. The research shows that the UMSA platform allows precise determination and calculation of thermal parameters. The influence of the heat treatment on structure and properties of aluminium castings has been determined as well. Heat treatment was carried out to increase the mechanical properties of aluminium alloys. Based on the findings above, the influence of microstructure on properties of the alloys is discussed.

Wrought aluminium–magnesium alloys subjected to SPD processing

Abstract The article presents the influence of stationary plastic deformation, using the equal channel angular pressing (ECAP) method, on the structure and properties of an aluminium alloy with 3 % magnesium content. In order to investigate changes in the structure and substructure, light microscopy and transmission electron microscopy were used. The influence of plastic deformation was determined by hardness measurement using the Vickers method. The results of the investigation show that, even after one ECAP, it is possible to decrease grain size to a range of 30 – 70 nm, and increase the mechanical properties by nearly 90 %. It was also found that the additional twist angle of the die has a minor effect on the properties and structure of the investigated alloy.

Strength and structure of AlMg3 alloy after ECAP and post-ECAP processing

ABSTRACT Equal-channel angular pressing (ECAP) is a promising method for the processing of metals with an ultrafine-grain (UFG) structure of a few hundred nanometers in size. In this paper, the influence of solution treatment and artificial aging conditions, combined with a severe plastic deformation process on the AlMg3 aluminum alloy, was studied. Samples were processed up to six passes with the application of processing route Bc, in which the sample after each separate pass is rotated clockwise by 90 degrees. Optical microscopy and electron backscattered diffraction were used to investigate the microstructure evolution at particular stages of the investigation. To estimate the effect of the process parameters on the change of the strength of the alloy, tensile properties and hardness measurements were determined.

Mechanical properties and structure of AZ61 magnesium alloy processed by equal channel angular pressing

An equal channel angular pressing (ECAP) procedure has been developed to produce a fine-grained AZ61 magnesium alloy. The results show that the microstructure can be effectively refined with increasing equivalent strain during ECAP. For increasing ECAP process efficiency was conventional tool as a helix in the horizontal part of channel built. This fine-grained alloy has an excellent strength accompanied by reasonable good tensile ductility. The success of the development of this ECAP procedure can offer a good opportunity for the development of magnesium alloys with good mechanical properties.

Effect of ECAP Strain on the Precipitation Kinetics of the AlMg3 Aluminium Alloy

Variation of hardness and microstructure evolution in a solution treated AlMg3 aluminium processed by equal channel angular pressing and subjected to subsequent artificial ageing are investigated. The microstructure features of the UFG aluminium alloy are studied by light, electron microscopy and using X-ray diffraction analysis. Microstructural observations showed significant grain refinement. After four ECAP passes microstructure consist of elongated grains with average widths of shear bands of ∼100 nm. A significant increase in the microhardness was observed in the ECAPed samples due to the grain refinement and strain hardening. Prior ECAP solution treatment and a short time artificial ageing can additionally increase the strength of AlMg3 aluminium alloy.

Effect of Heat Treatment Combined with High Pressure Torsion Process on Microstructure and Hardness of AlMg5Si2Mn Alloy

This study evaluated the effect of a heat treatment on the potential application of AlMg5Si2Mn die casting alloy as a substitute for wrought aluminium alloy products. The proposed heat treatment was intended to increase the workability of the AlMg5Si2Mn alloy, which is typically not malleable due to the presence of interconnected brittle phases. By disintegrating interconnected eutectic Mg2Si phases into fragmented particles and dissolving Mg-rich phases the workability was increased. Subsequently, heat treated samples were subjected to high-pressure torsion process. The microstructure of the heat treated and deformed samples were characterized using light and electron microscope. Hardness measurements were used to investigate the influence the number of HPT revolutions on mechanical properties.