Accession Number : ADA288923

Title :   Strengthening of NiAl Matrix Composites.

Descriptive Note : Annual rept. 1 Oct 93-30 Nov 94,

Corporate Author : MARYLAND UNIV COLLEGE PARK METALLURGICAL MATERIALS LAB

Personal Author(s) : Arsenault, R. J.

PDF Url : ADA288923

Report Date : 30 NOV 1994

Pagination or Media Count : 86

Abstract : The significant result is that the observed strengthening due to various types reinforcements (Al203 and TiB2) with same size is almost identical. The smaller size reinforcement 5 micrometers vs 150 micrometers produces greater strengthening. Also, the strengthening due to Al2O3 whiskers, which have long l/d (length to diameter) ratios of 10 to 100 is no greater than particulate Al203 and TiB2 of approximately the same size, which is a further indication that a load transfer mechanism is not applicable for these composites. A detailed examination of the data still suggests that the thermally-activated-rate controlling mechanism is the stress assisted motion of jogged screw dislocations. The specific details of the process are now be worked out to be able to obtain the proper stress and temperature dependence of the activation parameters. The strengthening observed in the composites at both high and low temperatures is due to an increase in the internal stress. This internal stress is independent of test temperature and stress,

Descriptors :   *METAL MATRIX COMPOSITES, *STRENGTH(MECHANICS), *ALUMINUM, *NICKEL ALLOYS, STRESS ANALYSIS, INTERFACES, HIGH TEMPERATURE, ELASTIC PROPERTIES, ALUMINUM OXIDES, DUCTILITY, YIELD STRENGTH, FILAMENTS, SILICON CARBIDES, TITANIUM BORIDE, THERMAL STRESSES, REINFORCING MATERIALS, PLASTIC FLOW.

Subject Categories : Laminates and Composite Materials
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE