Accession Number : ADA311506

Title :   Fracture Resistance of Welded Aluminum AlMg4.5Mn for Application in Surface Ships.

Descriptive Note : Final rept. for 1995,

Corporate Author : METAALINSTITUUT TNO APELDOORN (NETHERLANDS)

Personal Author(s) : Koning, C.

PDF Url : ADA311506

Report Date : 12 APR 1995

Pagination or Media Count : 59

Abstract : The most important requirement for a constructional material from the viewpoint of safety is avoidance of brittle fracture. Especially for the combination of lower temperature and high strain rate during explosive blast loading, initiation and propagation of brittle fracture can occur in ship's material with plate thicknesses of 6/15 mm. These plates are being used for the fabrication of surface ships of the Royal Dutch Navy. In this report the fracture resistance was determined of welded aluminum AlMg4.5Mn (5083 series) with a plate thickness of 10 mm. The results of Charpy tests at -5 deg C of the weldment show that the lowest notch toughness was measured for Charpy specimens with the notch on the fusion line. The results of quasistatic CTOD tests at -5 deg C on B x 2B 3-point bending specimens with through thickness cracks on the fusion line, ratio crack length/ width a/W approx. 0.5, show a lowest CTOD of 0.06 mm. From these results it is obvious that the weldment may have a low fracture toughness at -5 deg C. The results of dynamic CTOD tests at -5 deg C on B x 5B 3-point bending specimens with through thickness cracks on the fusion line, ratio crack length/ width a/W approx. 0.3, are: The lowest CTOD is 0.13 mm, the average K (Jc) is 52 MPa square root of m, with a lowest value of 50 MPa square root of m. The results of the dynamic CTOD tests show that the fracture toughness of the weldment in AlMg4.5Mn investigated, is not strain rate sensitive.

Descriptors :   *RESISTANCE, *FRACTURE(MECHANICS), *WELDMENTS, *ALUMINUM, *SURFACE EFFECT SHIPS, PROPAGATION, MAGNESIUM, THICKNESS, LOW TEMPERATURE, HIGH RATE, OCEAN SURFACE, NETHERLANDS, MATERIALS, NAVY, CRACKS, FABRICATION, TOUGHNESS, EXPLOSIVES, STRAIN RATE, BRITTLENESS, PLATES, BLAST LOADS, CHARPY IMPACT TESTS, AVOIDANCE, DUTCH LANGUAGE, NOTCH TOUGHNESS, MANGANESE.

Subject Categories : Properties of Metals and Alloys
      Inorganic Chemistry
      Marine Engineering
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE