Effect of Surface Finish and Temperature on Low Cycle Fatigue Behavior
of GRCop-42
Abstract
This study investigates the impact of various surface finishes on the
low cycle fatigue (LCF) properties of laser powder bed fusion GRCop-42.
The evaluated surfaces include as-built, machined, and chemically
polished finishes (1 .0% and 2 .0%). LCF life of
polished GRCop-42 was assessed at cryogenic (−195 ◦ C ), ambient, and
elevated temperatures (200 ◦ C , 400 ◦ C , 600 ◦ C , and 800 ◦ C )
across three strain amplitudes. Results indicate that surface finish has
minimal impact on LCF life. Stress across different strain levels showed
minimal effect of surface finish on cyclic hardening/softening.
Cryogenic temperatures led to cyclic hardening followed by
stabilization, while ambient and 200 ◦ C temperatures showed initial
hardening followed by softening. At 400 ◦ C and above, specimens
displayed continuous cyclic softening. Fractography showed that surface
finish impacts plastic deformation: as-printed and polished surfaces had
brittle fractures, while machined specimens were ductile. Specimens at
cryogenic and ambient temperatures exhibited brittle fractures, whereas
those at elevated temperatures showed plastic deformation and
microcracks.