Evaluation of linear friction welds in cast nickel-base superalloys

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:115483

Sampath, K; Green, R S

Cast nickel-based superalloys are commonly used in the manufacture of {open_quotes}blisks.{close_quotes} Blisks are combined turbine blade and disk assemblies used in advanced aircraft engines. Repair of refurbishment of blisks during engine repair or overhaul often involves the application of suitable fusion welding methods. Compared to fusion welding methods, the minimum heat input and the narrow heat- and deformation-affected zone (HAZ) associated with the linear friction welding (LFRW) process, and the minimal access required to produce the weld joint are expected to enable successful repair or refurbishment of blisks. This investigation evaluated the feasibility for using the LFRW process to produce metallurgically acceptable weld joints in cast IN738LC, Rene 80, Rene 80DS nickel-based superalloys. Similar metal combination LFRW were produced between rectangular bars (4 in. long, 1/2 inc. thick and 1 in. wide) of these alloys. Subsequently, a detailed metallurgical evaluation of the weld joints was performed using mechanical property testing and metallurgical characterization, which included room-temperature tensile testing (per ASTM E-8) of base metal and transverse-weld specimens, Charpy impact testing of both base metal and weld, light microscopy examination of the weld zone, and Vickers microhardness traverses (500 g load) across the weld joint, both along the weld center and near the weld outer periphery. The LFRW in cast IN738LC, Rene 80, Rene 80DS alloys showed satisfactory room-temperature weld mechanical properties and a homogenized microstructure in the weld zone. The weld mechanical property test results were consistent with the microstructural transitions observed in the weld zone. These results indicated that the LFRW process can be applied in blisk repair or refurbishment to produce metallurgically acceptable weld joints. Future investigations can be directed to evaluate the high temperature behavior of these weld joints.

• OSTI ID: 115483
• Report Number(s): CONF-9404233--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHARPY TEST
FRICTION WELDING
HARDNESS
HEAT AFFECTED ZONE
HEAT RESISTING ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL BASE ALLOYS
RENE 80
TENSILE PROPERTIES
WELDED JOINTS
YIELD STRENGTH