A. Sengupta et al., TENSILE BEHAVIOR OF A NEW SINGLE-CRYSTAL NICKEL-BASED SUPERALLOY (CMSX-4) AT ROOM AND ELEVATED-TEMPERATURES, Journal of materials engineering and performance, 3(5), 1994, pp. 664-672
Tensile behavior of a new single-crystal nickel-based superalloy with
rhenium (CMSX-4) was studied at both room and elevated temperatures. T
he investigation also examined the influence of gamma' precipitates (s
ize and distribution) on the tensile behavior of the material. Tensile
specimens were prepared from single-crystal CMSX-4 in [001] orientati
on. The test specimens had the [001] growth direction parallel to the
loading axis in tension. These specimens were given three different he
at treatments to produce three different gamma' precipitate sizes and
distributions. Tensile testing was carried out at both room and elevat
ed temperatures. The results of the present investigation indicate tha
t yield strength and ultimate tensile strength of this material initia
lly increases with temperature, reaches a peak at around 800 degrees C
, and then starts rapidly decreasing with rise in temperature. Both yi
eld and tensile strength increased with increase in average gamma' pre
cipitate size. Yield strength and temperature correlated very well by
an Arrhenius type of relationship. Rate-controlling process for yieldi
ng at very high temperature (T greater than or equal to 800 degrees C)
was found to be the dislocation climb for all three differently heat-
treated materials. Thermally activated hardening occurs below 800 degr
ees C whereas above 800 degrees C thermally activated softening occurs
in this material.