ELECTRON FRACTOGRAPHY AND FATIGUE CRACK PROPAGATION IN 7075-T6 ALUMINUM SHEET

A CENTRALLY SLOTTED 0.125 INCH THICK SHEET OF 7075-T6 ALUMINUM ALLOY WAS CYCLICALLY LOADED. STRIATION SPACINGS AND CRACK PROPAGATION RATES ON THE SPECIMEN SURFACE WERE MEASURED AND COMPARED, AND THE FRACTOGRAPHS WERE EXAMINED. THE AVERAGE STRIATION SPACING IS FOUND TO BE PROPORTIONAL TO A CERTAIN VALUE OF THE STRESS INTENSITY FACTOR RANGE WHILE THE SURFACE CRACK PROPAGATION RATE IS PROPORTIONAL TO A SLIGHTLY HIGHER VALUE. CLEAVAGE FRACTURES OF BRITTLE PARTICLES APPEAR TO CAUSE A DIFFERENCE BETWEEN THE OVERALL SURFACE CRACK PROPAGATION RATE AND STRIATION SPACINGS. IN THE LOWER STRESS INTENSITY FACTOR RANGE, THERE ARE FEWER CLEAVAGE FRACTURES. THE STRIATIONS ARE MORE DISTINCT AND THE DIRECTIONS OF THE STRIATIONS DO NOT DEVIATE MUCH FROM THE NORMAL TO THE DIRECTION OF THE OVERALL CRACK PROPAGATION. IN THE HIGHER STRESS INTENSITY FACTOR RANGE, THERE ARE MORE CLEAVAGE FRACTURES. IN THIS REGION, STRIATIONS RUN IN DIVERGENT DIRECTIONS AND BECOME LESS EVIDENT. THE DIFFERENCES IN FRACTURE SURFACE FEATURES RESULT FROM THE CLEAVAGE FRACTURE OF BRITTLE PARTICLES.

  • Corporate Authors:

    N/A

    ,   United States 
  • Authors:
    • Kershaw, J
    • Liu, Han-Wen
  • Publication Date: 1971-9

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  • Accession Number: 00209929
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 15 2003 12:00AM