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This research aims to evaluate horizontal and vertical constrained rod casting (CRC) molds on hot tearing susceptibility (HTS) of Al-xCu casting alloys with 2.2, 3.6, 7.5, and 12.5 percent Cu. The hot tears on the casting product were observed using a macroscopic approach. In addition, the hot tearing susceptibility of each casting product prepared using these molds was evaluated using the HTS formula. The results show that the vertical CRC mold has a higher HTS value than the horizontal CRC mold. The rod length is a significant factor in causing hot tearing. Longer rods are more susceptible to hot tearing. The horizontal CRC mold provides a clearer effect of rod length and Cu composition on the average HTS value. In the vertical CRC mold, the effect of Cu composition on the average HTS value is less clear. Therefore, it is highly recommended to use horizontal CRC mold for HTS testing of aluminum casting alloys. [ABSTRACT FROM AUTHOR]

Due to their low mechanical strength, the limited applications of fused filament fabrication (FFF)-printed products eventually intrigued researchers to overcome this problem through several approaches. Powder addition reinforcement (PAR) has been recognized as the oldest among the proposed techniques. However, several studies have shown the drawbacks of this technique concerning the poor bond between the printed polymer matrix and powder filler, as well as the nozzle clogging that often occurs during the printing process. In this study, a novel powder addition method using equipment that enables powder delivery with a continuous and intermittent flow was conducted. A composite sample was prepared by printing polylactic acid (PLA) filament combined with iron oxide (Fe3O4) powder particles. The results showed that the printed PLA/Fe3O4 samples obtained from processing with intermittent particle flow had better quality compared to those processed by continuous particle flow. However, both the continuous and intermittent powder addition experienced a negative effect due to rapid cooling caused by air exposure during the printing process. Nonetheless, the novel technique proposed in this study could show the ability to avoid nozzle clogging that might occur during the printing of PLA/Fe3O4 composite samples. [ABSTRACT FROM AUTHOR]