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    An experimental study to evaluate the warpage and cracking issues in fused deposition modeling
    (Pleiades journals, 2019) Suhas, A.; Rajpal, R.; Gangadharan, K.V.; Umesh, U.
    Research in 3D printing technology is growing immensely because of the advantage of manufacturing complex shapes in less time as compared to conventional manufacturing processes. However, warpage and cracking are the critical issues in fused deposition modeling technique which results in a reduction in the strength of the component. This paper aims to address the root causes for reducing the warpage and cracking in a 3D printed component. Fused-deposition-modeling-based 3D printer is used in this study to manufacture the samples. The behavior of warpage and cracking in the specimens are studied by altering bed temperature and extrusion width of the filament. The experimental results revealed that printing a component at 100 °C and 0.75 mm extrusion width led to minimum warpage and no crack condition. © Springer Nature Singapore Pte Ltd. 2019.
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    Failures Investigation of Marine Propellers in Corrosive Environments
    (Springer Nature, 2021) Mirashi, V.U.; Johnson, S.; Hegde, S.; Vijayan, V.; Cadambi, S.
    Marine corrosion failure of fishing boat propellers made of cast Nickel Aluminium Bronze were investigated. Specimens extracted from the corroded propellers were characterized by optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy. The alloy comprises several Fe3Al (κ1, κ2, κ4), NiAl (κ3) type intermetallic precipitates and β’ martensite embedded in Cu-rich α-matrix. Transverse sections of the corroded region showed two distinct zones; a non-uniform top oxide layer and a partially corroded zone with selective corrosion of the β’ martensite which run parallel to the κ3 precipitates. From the microstructural analysis it is adjudged that the aggressive local corrosion of the matrix is preceded by cracking of the oxide by erosion, cavitation, etc., A slow growth of the oxide layer follows that reduces the corrosion rate. However, the corrosion cycle repeats on erosion or cracking of the oxide layer when the propeller is used in marine waters. Coupon specimens immersed in actual marine conditions is presented that supports the above theory. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.