Processing and microstructure of a Cu-Al-Fe-Mn alloy via droplet-on-demand additive manufacturing
Kellen D. Traxel, Eric S. Elton, Amelia M. Petersen, Chinthaka M. Silva, Aurélien Perron, Jason R. Jeffries, Andrew J. Pascall
Abstract
Control over the microstructure and properties of alloys produced via additive manufacturing (AM) is a key barrier that limits widespread industrial adoption. Herein we demonstrate that liquid metal jetting (LMJ), an emerging metal-AM technique, can address this need by controlling the microstructure evolution during printing of bronze alloy C95400 (Cu-Al-Fe-Mn). We probed several solid-state phase transformations upon cooling by printing single-tracks onto a heated baseplate ranging from 50°C-600°C surface temperature, which led to significant variation in the α-Cu and δ-Fe phase distribution, grain morphology, and chemical distribution within the deposited single-tracks. The printed microstructures exhibited as much as 80% difference in α-Cu grain size and nearly 30% difference in α-Cu phase fraction due to baseplate temperature variation, indicating a wide range of available microstructures and properties achievable. Greater than 92% dense multi-layer samples were fabricated with fine grain structure and 27-34% higher hardness values to the barstock in the as-printed condition, demonstrating the applicability of this printing approach for multi-layer part fabrication. Our results highlight a unique microstructure tailoring capability for metal-AM parts that can be leveraged by manufacturers and end-users of AM technologies.