A method for heat treating metal alloy powder includes (a) introducing metal alloy powder to a chamber having a floor and a sidewall; (b) flowing a fluidizing gas through the floor and into the chamber to fluidize the metal alloy powder in the chamber; (c) flowing an additional gas through the sidewall into the chamber; and (d) heating the chamber to heat treat the metal alloy powder in the chamber. A system for heat treating metal alloy powder includes an inner chamber having a porous floor and a porous sidewall; an outer chamber, the inner chamber being inside of the outer chamber and defining an annular space between the outer chamber and the inner chamber, wherein the outer chamber and the inner chamber are inside a furnace; a source of fluidizing gas connected to the porous floor through the annular space; and a source of additional gas communicated with the porous sidewall through the annular space.