Influence of hot isostatic pressing on the performance of aluminum alloy fabricated by ultrasonic additive manufacturing

Ultrasonic additive manufacturing (UAM) is a solid-state manufacturing technique employing principles of ultrasonic welding coupled with mechanized tape layering to fabricate fully functional parts. However, UAM-fabricated parts often exhibit a reduction in strength when loaded normal to the welding interfaces (Z-direction). Here, the effect of hot isostatic pressing (HIP) on UAM builds of aluminum alloy was explored. Tensile testing and microstructure characterization were conducted; it was established that HIP eliminated the brittle Z-direction fracture and improved the strength and ductility of the Z-direction specimens. HIP eliminated voids and produced recrystallized structure; however, welding interfaces survived the HIP treatment.