The influence of residual stress on fatigue crack growth rates of additively manufactured Type 304L stainless steel

To examine the influence of residual stress on mechanical performance, specifically fatigue crack growth resistance, additively manufactured (AM) Type 304L stainless steel produced by directed energy deposition (DED) was evaluated and compared to conventional wrought 304/304L steel. Increasing decreasing alternating intensity factor (?K) tests were used assess behavior over a range rates in near threshold regime (<10-8 m/cycle). Bulk (Kres) profiles specimen measured using incremental slitting method. Tensile at edges DED materials led positive values Kres faster material as same applied ?K. Correcting for effects closure commercially available shows that are similar ?K lower than 6 MPa·m0.5.