Additive manufacturing of metals at high rate yielding controlled microstructure

摘要

Additive manufacturing, AM, of metals can be accomplished by sequentially melting and solidifying a feedstock to create a freeform shape. In terms of commercial machines the most common feedstocks are flowable metal powders. However, wire feedstock offers advantages in many situations. Many are derived from connection to a large established industrial base (welding) and include a range of available compositions (including cored wire), high material utilization, and relative economy. While AM by localized fusion offers geometrical flexibility, but at a cost and with property compromises associated with the lack of familiar metallurgical processing tools such as mechanical working. Energy efficiency can be limited by sequential heating and reheating the same volume element. Defects arise; in part, this is more likely due to the high specific surface area of feedstock(s).