| Abstract Scope |
Additive friction stir deposition is an emerging solid-state additive process that combines the friction stir principle with a continuous material feeding mechanism to allow for site-specific deposition. It enables large-scale additive manufacturing and repair for a broad range of engineering alloys and metal matrix composites, including those traditionally classified as nonweldable alloys. While beam-based metal additive processes involve powder melting and rapid solidification, and suffer from problems like high residual stresses, porosity, and hot cracking, additive friction stir deposition fundamentally avoids these issues while resulting in equiaxed, fine microstructures with superior mechanical properties. In this talk, I will discuss the most recent advances in additive friction stir deposition of Al, Cu, as well as Al-Mo and Al-ZrO2 composites. Of particular interest are the novel dynamic phase and microstructure evolution phenomena enabled by the extreme thermomechanical conditions during deposition, which involve high strain rate, high peak temperature, and large shear strain. |