Accession Number:

ADA139290

Title:

A Study of Fatigue Crack Propagation in Powder Metallurgy Hot Isotatically Pressed Nickel-Base Alloy.

Descriptive Note:

Annual rept. 1 Jan-31 Dec 83,

Corporate Author:

LEHIGH UNIV BETHLEHEM PA DEPT OF METALLURGY AND MATERIALS ENGINEERING

Personal Author(s):

Report Date:

1984-01-31

Pagination or Media Count:

11.0

Abstract:

Initial efforts were addressed at the preparation of powders that would result in the development of HIPd logs possessing a large range of grain sizes and grain size distributions. After several trials, it was determined that the widest range of alloy grain size could be obtaining by using different HIPing temperatures in conjunction with different solution treatments ST. The following treatments and grain sizes are identified 1107 C HIP 1121 C ST ASTM No. 13 1107 C HIP 1149 C ST Duplex size ASTM average 8-9 1107 C HIP 1177 C ST ASTM No. 6-6.5 1246 C HIP 1149 C ST ASTM No. 4. Further aging treatments are planned at 650 C and 800 C to obtain fine and coarse gamma precipitate sizes, respectively. Initial fatigue crack propagation tests were completed with both material and computer-controlled test system performing in a well behaved manner. Crack closure measurements were obtained which allowed crack growth rate data to be compared with delta K sub eff. Grips and fixtures have been designed and ordered which will permit cyclic strain experiments to be conducted at both room and elevated temperatures. Techniques were developed to prepare thin foils to allow for detailed examination of alloy microstructures and cyclic load-induced dislocation structures.

Subject Categories:

  • Properties of Metals and Alloys
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE