Aluminum alloys, known for their high strength-to-weight ratios and impressive electrical and thermal conductivities, are extensively used in numerous engineering sectors, such as aerospace, automotive, and construction. Recently, significant efforts have been made to develop novel aluminum alloys specifically tailored for additive manufacturing. These new alloys aim to provide an optimal balance between mechanical properties and thermal/ electrical conductivities. In this study, nine combinatorial samples with various alloy compositions were fabricated using direct energy deposition (DED) additive manufacturing by adjusting the feeding speeds of Al6061 alloy and Al-12Si alloy powders. The effects of the alloying elements on the microstructure, electrical conductivity, and hardness were investigated. Generally, as the Si and Cu contents decreased, electrical conductivity increased and hardness decreased, exhibiting trade-off characteristics. However, electrical conductivity and hardness showed an optimal combination when the Si content was adjusted to below 4.5 wt%, which can sufficiently suppress the grain boundary segregation of the α- Si precipitates, and the Cu content was controlled to induce the formation of Al2Cu precipitates.

A 4-day-old, male Poodle dog was presented with dull, depressed and exhausted activity after the birth. On physical examination, the puppy showed arthrogryposis, muscular atrophy and no movement of hindlimbs. Palpation on dorsum revealed an absence of lumbar and sacral vertebrae. On prenatal and postnatal radiography, lumbar vertebrae, sacrum and coccygeal vertebrae were not visualized. On ultrasonography, bilateral kidney and urinary bladder were observed. On computed tomography, there were no apparent abnormalities in the forelimbs, cervical vertebrae or head, while lumbar vertebrae, sacrum and coccygeal vertebrae were not observed. At necropsy examination, the liver, stomach, intestine, kidney and urinary bladder were normal. This congenital anomaly was consistent with Perosomus elumbis. Perosomus elumbis in dogs is a rare condition of unknown etiology. In this report, Perosomus elumbis was evaluated with radiography, ultrasound and computed tomography.