Heat treatment studies of Al-Zn-Mg alloy forgings of the DTD 5024 type

Porgings were given a variety of heat treatments after which hardness, static tensile properties, fatigue properties, fracture toughness and stress corrosion resistance were determined. Microstructures were studied in the electron mcroscope using the thinfoil technique. The effect of heat treatment on the microstructure could be explained on the...

Ontwikkelingen op hetgebied van de resultaten van kuipproeven : de evolutie van de parametermethode

The concept of a time-temperature parameter is described. Methods are discussed for determining optimal values for the constants that appear in these parameters. These methods include the least squares approach, the use of orthogonal polynomials and Manson's new "minimum commitment station-function approach". Finally the effects of micro...

Correlations involving properties and microstructures of Al-An-Mg alloy forgings of the 7079 type

Correlation diagrams show that fracture toughness and fatigue crack propagation resistance are closely related properties, while stress corrosion endurance is a crack tolerance property with different characteristics. The heat treatment effects on characteristic dimensions of the microstructure could generally be explained on the basis of...

The repair of fatigue cracks in low-alloy steel sheet

Fatigue cracks were grown in rectangular specimens with a central notch. At a certain crack length, the crack was repaired, using a variety of methods. Fatigue loading was resumed and re-initiation and subsequent growth of the fatigue crack were studied. The repair methods evaluated comprised simple stopholes, brazed straps across the crack,...