Thermal–Mechanical Working of Spark Plasma Sintered Preforms Fabricated from Aluminum 2219 Powder

Abstract

The effects of spark plasma sintering (SPS) coupled with hot upset forging of aluminum 2219 powder were studied. SPS was found to be an effective means of consolidating the powder as select specimens achieved full theoretical density. Although these as-sintered products also demonstrated a reasonable combination of tensile properties, they were greatly improved after forging. The most acute gains were observed in tensile ductility wherein three to four times improvements transpired. TEM analyses confirmed that forging manifested an appreciable disruption of the residual oxide networks present in the as-sintered product which was believed to be the primary driver of tensile property enhancements. SPS + forge products were also responsive to T87 heat treatment. Typical T87 values for tensile yield strength, UTS, and elongation to fracture were 350 MPa, 465 MPa, and 10 pct, respectively. Interestingly, these values were attainable over a wide range of sintering and forging temperatures. TEM analyses confirmed that θ′ was the dominant precipitate present in the SPS + forge-T87 products.