The effect of the modification by ultrafine silicon carbide powder on the structure and properties of the Al-Si alloy

Abstract

Purpose: Determine the possibility of modifying aluminium alloys of the Al-Si system with an ultrafine SiC modifier with a particle size of 3-5 μm. Design/methodology/approach: Processing of the Al-Si alloy was carried out by introducing an ultrafine modifier in the amount of 0.1, 0.2, or 0.3 wt.%. Silicon carbide (SiC) with a particle size in the range of 3-5 μm was used as a modifier. To study the microstructure of the formed surface layers, a metallographic analysis was performed according to the standard method on a microscope MIKPOTEX® MMT-14C using TopView software. Microhardness studies of the samples were carried out on a Vickers microhardness tester NOVOTEST TC-MKV1. The microstructure of castings of the AlSi12 grade was studied at magnification from 100 to 400 times on the horizontal and vertical surfaces of the samples after etching with a 2% NaOH aqueous solution. Findings: Aluminium cast alloy of Al-Si system has been synthesized with the addition of 0.1, 0.2, and 0.3 wt.% ultrafine SiC modifier. It was found that the modification of the AlSi12 alloy by SiC particles of 3-5 μm in size led to an improvement of its microstructure due to the reduction of the volume fraction of micropores and primary Si crystals. It was shown that the AlSi12 aluminium alloy due to the modification by 0.2 wt.% SiC has the best micromechanical properties and macrostructure density. Research limitations/implications: The obtained research results are relevant for cast specimens of the indicated sizes and shapes. The studies did not take into account the influence of the scale factor of the castings. Practical implications: The developed modification technology was recommended for use in the conditions of the foundry "Dnipropetrovsk Aggregate Plant" (Dnipro, Ukraine). Originality/value: The technology of AlSi12 alloy modification of ultrafine SIC modifier with a particle size of 3-5 μm was used for the first time.

Analysis of scooter engine piston damage

“…A more likely cause of the formation of the inflow, taking into account the location of this defect, the complex shape of the ingot, and the serial production, is damage to the rod during mold casting. Mold casting is much cheaper and more efficient for this ingot [18], but the complex structure requires the installation of a rod to form a hole for the connecting rod finger. The use of a metal rod, despite greater accuracy, requires adaptation of the mold shape, namely the creation of its detachable version, which will be assembled before pouring.…”