TY - JOUR
AU - Kim, Young-Won
AB - Alloy 4822 (Ti-48Al-2Cr-2Nb at. pct) cast material was given a controlled heat treatment cycle to generate a casting nearly lamellar (CNL) microstructure that enhances the temperature capability over its current engineering casting duplex (CDP) microstructure form. The cycle consisted of three steps: a short α field annealing, an α + γ field annealing, and then aging at a low temperature, with each step being followed by controlled cooling. The resulted microstructure is shown to be a mixture of non-uniformly distributed ~ 250 μm size lamellar colonies containing ~ 0.15 µm spaced laths. Standard tensile testing at 700 °C shows a yield stress of 344 MPa that is ~ 55 MPa greater than that of the current engineering CDP form. The sequential microstructure evolution processes following the three-step thermal cycle are assessed and explained in terms of phase transformations taking place across and below the α transus upon isothermal treatment and subsequent cooling. The resulted increases in high-temperature strengthening are explained by the colony and γ grain size distributions. The strengthening mechanism along with the significance is discussed.
TI - A Newly Generated Nearly Lamellar Microstructure in Cast Ti-48Al-2Nb-2Cr Alloy for High-Temperature Strengthening
JO - Metallurgical and Materials Transactions A
DO - 10.1007/s11661-019-05491-8
DA - 2019-10-11
UR - https://www.deepdyve.com/lp/springer-journals/a-newly-generated-nearly-lamellar-microstructure-in-cast-ti-48al-2nb-dcNxbdEVS1
SP - 5839
EP - 5852
VL - 50
IS - 12
DP - DeepDyve
ER -