
Accession Number : ADA299687
Title : Fatigue Crack Growth Behavior of a Titanium Matrix Composite Under Thermomechanical Loading.
Descriptive Note : Doctoral thesis,
Corporate Author : WRIGHT LAB WRIGHTPATTERSON AFB OH
Personal Author(s) : Blatt, Paul A.
PDF Url : ADA299687
Report Date : DEC 1993
Pagination or Media Count : 240
Abstract : The crack growth characteristics of a 4ply, unidirectional, titanium matrix composite, SCS6/ti6Al2Sn4Zr2Mo, subjected to thermomechanical fatigue were investigated. A linear summation model was developed to predict the isothermal and thermomechanical fatigue (TMF) crack growth rates of the composite. The linear summation approach assumes the total fatigue crack growth rate is a combination of a cycledependent and a timedependent component. To assist the modeling effort, a series of isothermal, inphase, and outofphase crack growth test were conducted. The test temperatures ranged from 15000 to 53800 and the fastest thermal frequency was 0.0083 Hz. With the excepton of the 15000 isothermal test, the model was able to correlate all the baseline fangue crack growth test data between oK of 50 to 9OMPa. In additon, the model was able to predict the fatigue crack growth rate of a proof test which involved a continual change in temperature range and load range to produce a constant crack growth rate. The proof test began under isothermal conditions at the maximum temperature and ended under inphase TMF conditions.
Descriptors : *METAL MATRIX COMPOSITES, *CRACK PROPAGATION, *FATIGUE(MECHANICS), *THERMAL FATIGUE, *AEROSPACEPLANES, *TITANIUM ALLOYS, THERMOMECHANICS, AIR BREATHING ENGINES, NONDESTRUCTIVE TESTING, HIGH TEMPERATURE, FINITE ELEMENT ANALYSIS, DAMAGE ASSESSMENT, FIBER REINFORCED COMPOSITES, THESES, FABRICATION, MOLYBDENUM, TOUGHNESS, MATRIX MATERIALS, CHEMICAL COMPOSITION, IMPACT STRENGTH, COMBUSTION, GAS TURBINES, ALUMINUM, THERMAL EXPANSION, LIGHTWEIGHT, ZIRCONIUM, DUCTILITY, TOLERANCES(MECHANICS), AEROSPACE INDUSTRY, SILICON CARBIDES, THERMAL STRESSES, HYPERSONIC VEHICLES, ISOTHERMS, CREEP STRENGTH.
Subject Categories : Laminates and Composite Materials
Properties of Metals and Alloys
Thermodynamics
Research and Experimental Aircraft
Distribution Statement : APPROVED FOR PUBLIC RELEASE