several derivative alloys at 103.5 MPa (15 KSI) and 1093'C (2000'F). Rupture lives of the modified SC alloys were significantly affected by both alloy purity and heat treatment. Critical aspects of vacuum induction refining, exothermic casting technology, alloy development and heat treatment, which contributed to this new class of turbine blades, are reviewed.

No abstract

A low-cost process for casting directionally-solidified CDS) turbine blades of high stress-rupture strength has been successfully developed. The process employs an exothermically heated mold to produce DS castings. Using this process, a newly designed solid blade for the high-pressure turbine of the Garrett TFE731-3 turbofan engine was cast in the Mar-M 247 and Mar-M 2OOcHf alloys and engine-tested. The solid DS blade replaced a cooled, conventionally cast INIOO blade. An engine test in this research and development program! showed a 2.4-percent reduction in takeoff specific fuel consumption. An estimated 40-percent reduction in finished turbine blade cost was realized. As a result, the new DS Mar-M 247 blade has been selected for production in the TFE731-B-100, an advanced version of the TFE731-3 engine.

No abstract

REPOT DCUMNTATON AGEREAD INSTRUCTIONS REPOR DOCMENTTIONPAGEBEFORE COMPLETING3 FORM F If0W'MBER 2.GOVT ACCESSION No. 3. RECIPIENT*S CATALOG NUMBER 4. TTE Fujbtgl)