Material Characterization and Real-Time Wear Evaluation of Pistons and Cylinder Liners of the Tiger 131 Military Tank

Material characterisation and wear evaluation of the original and replacement pistons and cylinder-liners of Tiger 131 is reported. Original piston and cylinder-liner were operative in the Tigers’ engine during WWII. The replacement piston and cylinder-liner were used as substitutes and were obtained after failure in two hours of operation in the actual engine. Material characterisation revealed that the original piston was aluminium silicon hypereutectic alloy whereas the replacement piston was aluminium copper alloy with very low silicon content. Both original and replacement cylinder-liners consisted of mostly iron which is indicative of cast iron, a common material for this application. The replacement piston average surface roughness was found to be 9.09 μm while for replacement cylinder-liner it was 5.78 μm

Effect of intensive melt shearing on the formation of Fe-containing intermetallics in LM24 Al-alloy

Fe is one of the inevitable and detrimental impurities in aluminium alloys that degrade the mechanical performance of castings. In the present work, intensive melt shearing has been demonstrated to modify the morphology of Fe-containing intermetallic compounds by promoting the formation of compact α-Al(Fe,Mn)Si at the expense of needle-shaped β-AlFeSi, leading to an improved mechanical properties of LM24 alloy processed by MC-HPDC process. The promotion of the formation of α -Al(Fe, Mn)Si phase is resulted from the enhanced nucleation on the well dispersed MgAl 2O 4 particles in the melt. The Fe tolerance of LM24 alloy can be effectively improved by combining Mn alloying and intensive melt shearing

In situ alloying of elemental Al-Cu12 feedstock using selective laser melting

This investigation developed selective laser melting (SLM) processing parameters for the in situ fabrication of an Al-Cu12 alloy from pure elemental blends of aluminium and copper powders. Use of elevated pre-heat temperatures (400°C) created a coarser dendritic cell microstructure consisting of supersaturated Al-rich with a uniform Al 2 Cu phase granular microstructure compared to non-pre-heated samples. Al-Cu12 in situ samples achieved maximum tensile strength values comparable to that of sand cast pre-alloyed Al-Cu12. Processing at elevated pre-heat temperatures created components with higher ultimate tensile strength and ductility compared to standard room temperature-built samples due to it assisting a more complete melting of Al and Cu particles. Additionally pre-heating enabled an artificial age hardening, producing an equilibrium α + θ microstructure. The creation of an alloy in situ through the use of elemental powder blends represents a low-cost and flexible methodology for exploration of new SLM material compositions and potential candidate materials for semi-solid processing using SLM