Measuring the Fracture Toughness of TZM and ODS Molybdenum Alloys Using Standard and Sub-Sized Bend Specimens

Cockeram, B. V.

Bettis Atomic Power Laboratory

关键词: Molybdenum Alloys;    Testing;    Molybdenum;    Geometry;    36 Materials Science;   

DOI  :  10.2172/807260
RP-ID  :  B-T-3387
RP-ID  :  AC11-98PN38206
RP-ID  :  807260

美国|英语

来源: UNT Digital Library

【 摘 要 】

Oxide Dispersion Strengthened (ODS) and TZM molybdenum have excellent creep resistance and strength at high temperatures in inert atmospheres. Fracture toughness and tensile testing was performed at temperatures between -150 degrees C and 450 degrees C to characterize 6.35 mm thick plate material of ODS and TZM molybdenum. A transition from low fracture toughness values (5.8 to 29.6 MPa square root m) to values greater than 30 MPa square root m is observed for TZM molybdenum in the longitudinal orientation at 100 degrees C and in the transverse orientation at 150 degrees C. These results are consistent with data reported in literature for molybdenum. A transition to low fracture toughness values (less than 30 MPa square root m) was not observed for longitudinal ODS molybdenum at temperatures greater than or equal to -150 degrees C, while a transition to low fracture toughness values (12.6 to 25.4 MPa square root m) was observed for the transverse orientation at room-temperature. The fi ne spacing of La-oxide precipitates that are present in ODS molybdenum result in a transition temperature that is significantly lower than any molybdenum alloy reported to date, with upper bound fracture toughness values that bound the literature data. A comparison of fracture toughness values obtained using a 1T, 0.5T, and 0.25T Charpy shows that a 0.5T Charpy could be used as a sub-sized specimen geometry.