Influence Due Grenail.precon.sur Tenue Fatigue Et Sur La Corr.sous Tens.des All.d'alum.ser.5000/7000

Author:  Gaillard, Chouvy, Blechet, Moguerou
Source:  Conf Proc: ICSP-1, (p.501-508)
Doc ID:  1981032
Year of Publication:  1981
Tests have been carried out on butt-joints welded by MIG method with reinforcement off or as welded. Shot peening introduces in surface stresses of compression of 170 to 200 MPa, which have been determined by X-ray diffraction. The affected layer is .3 mm thick, whereas the pre-strained zone determined by micro-hardness measurement is .25 mm thick. The following aluminium alloys have been tested : 5086, 5083 H116 and H323, 7020 and a A-G4Z2 type. Corrosion fatigue tests have been carried out in a buffered salt solution (artificial sea-water),whereas stress corrosion tests have been carried out either in the artificial sea-water, or in a bichromate solution of pH3. The improvement on fatigue and corrosion fatigue strength is: - for plain plate : 20% for each case, - for joints with reinforcement off : 15 to 100% for fatigue and about 50% for corrosion fatigue, - for joints as welded : 80% for some cases. Stress corrosion results are note significant. The exfoliation corrosion of 7020 welded joints alloy is not modified by shot peening treatment. Descriptors: Aluminium alloys; Butt-joints; Fatigue; Corrosion fatigue; Stress-corrosion; Shot-peening

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