Chapter 15 - Transient thermal analysis in friction-stir additive manufacturing of dissimilar wrought aluminum alloys

Abstract

Friction stir additive manufacturing (FSAM) is a modern production operation for generating high-strength components of a controlled microstructure. Unlike conventional AM techniques, it does not require large infrastructure and is little more cost-effective approach especially for lightweight metals like aluminum, zinc, etc. Limited defects and fine microstructure of the final product have attracted the approach in recent times Here, a stack of plates made of the same or different materials kept in a lap configuration is friction stir welded two at a time to form the 3D component. Each of the two plates (one pass) is formed by moving a specially prepared spinning tool over the surface of the plates. Heat produced from friction and subsequent material mixing from the stirring of tool pin facilitates the formation of final product. The present chapter describes the methodology and types of additive friction stir manufacturing for aluminum alloys in detail. As the approach is similar to two-plate lap stir welding, modeling details of the lap welding have been addressed. A numerical model of stacked-based FSAM of aluminum alloys is presented for evaluation of mechanical and thermal characteristics of the process. Examples of additive friction stir manufacturing of four layered alternative stacks of aluminum alloys AA5251 and AA6063 are presented with a moving heat source model, and microstructure simulation issues are reviewed in general.