Comparison of Image Analysis Techniques for the Determination of the Influence of Melt Flow on the Solidification Microstructure of Technical Aluminum Alloys | Chapter 5 | | Proceedings of the 8th International Conference on Solidification and Gravity

This work aims to contribute to the improvement of automated analysis of 2D microstructures in technical aluminum alloys by evaluating the effectiveness of various microstructural image analysis methods: Traditional analysis techniques for 2D images and cutting-edge computer vision deep learning-based methods (Mask Region-based Convolutional Neural Networks or Mask R-CNN [1], a model used to detect the position and exact shape of objects) are compared for detecting, classifying, and quantifying microstructural features in technical iron containing aluminum alloys. Determining that deep learning-based methods lead to comparable or better results would allow for such models to be used for analysis of the chosen microstructural features. This could improve detection accuracy and speed, as well as measurement reproducibility.

The focus is on detecting and characterizing Fe-containing intermetallic phases that precipitate during solidification, with the aim of examining the effects of increased iron content on the microstructure of these alloys. Therefore, the microstructure of directionally solidified hypoeutectic AlSi6Cu4Fe1 and hypereutectic AlSi6Cu4Fe2 alloys is analyzed with regards to area fraction and size of the intermetallic precipitates within two distinct sample processing zones: the first half of the samples was solidified under diffusive mass transport conditions and the second under forced convective conditions, both in microgravity. This dual approach allows for the evaluation of the impact of convection on the microstructure of aluminum alloys with elevated iron content.

 

Author (s) Details

 

Golo Zimmermann
RWTH Aachen University, Foundry Institute, Intzestraße 5, 52072 Aachen, Germany.

 

Sonja Steinbach
Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.

Laszlo Sturz
ACCESS e.V., Intzestraße 5, 52072 Aachen, Germany.

 

Alexandre Viardin
ACCESS e.V., Intzestraße 5, 52072 Aachen, Germany.

 

Angelos Theofilatos
ACCESS e.V., Intzestraße 5, 52072 Aachen, Germany.

 

Florian Kargl
RWTH Aachen University, Foundry Institute, Intzestraße 5, 52072 Aachen, Germany and Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.

 

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-95-9/CH5

An Investigation on SiC and Al Surface Cladding of Ti-6Al-4V for Improved Wear Properties – The Binary Advantage | Chapter 6 | Current Approaches in Science and Technology Research Vol. 5

 Ti-6Al-4V has a high specific strength, toughness, and corrosion resistance, but it has a high friction coefficient, severe adhesive wear, and fretting wear sensitivity. One of the surface modification techniques used to improve on these flaws is laser surface cladding. Laser cladding makes use of the high power density of a focused laser source to heat and melt the surface of the substrate while injecting alloying elements into the melt pool. The surface cladding of the as-received Ti-6Al-4V alloy was done with different ratios of SiC and Al powders using a 4.4Kw continuous wave Nd-YAG laser processor. The SiC powder can act as reinforcing particles and aids in the construction process. The resulting surface metal matrix composite has improved surface wear properties, while aluminum improves wetting between the metal and the reinforcement SiC phase. However, the success of this is dependent on the careful optimization of the powder ratio, which dictates the resulting phases and microstructural evolutions. SEM (energy dispersive spectroscopy), optical microscopy, and x-ray diffraction analysis of the cladding revealed the formation of intermetallic phases such as AlSiTi2, Ti7Al5Si12, TiSi2, AlSi3Ti2, Al6Ti19, Ti2VAl, AlTi3, AlCTi2, Ti3SiC2 and Ti3SiC2. Ti5Si4, which should improve the surface's microhardness and tribological properties compared to the bulk as-received alloy. The best microhardness was 1169.95 Hv, compared to 323.67 Hv for the as-received, and mass loss under abrasive wear tests was only 40% of the as received. This improvement is also reflected in the morphology of the abraded surfaces. The binary combination of Al and SiC powders suffices for significantly improved Ti-6Al-4V surface properties in carefully optimized proportions and laser conditions. Ti5Si4, which should improve the surface's microhardness and tribological properties compared to the bulk as-received alloy. The best microhardness was 1169.95 Hv, compared to 323.67 Hv for the as-received, and mass loss under abrasive wear tests was only 40% of the as received. This improvement is also reflected in the morphology of the abraded surfaces. The binary combination of Al and SiC powders suffices for significantly improved Ti-6Al-4V surface properties in carefully optimized proportions and laser conditions.

Author (s) Details

U. O. Okoli
The Vaal University of Technology, Department of Metallurgical Engineering, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark, South Africa.

I. O. Otunniyi
The Vaal University of Technology, Department of Metallurgical Engineering, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark, South Africa.

I. D. Adebiyi
The Vaal University of Technology, Department of Metallurgical Engineering, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark, South Africa.

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