Corrosion Activity of Ultrafine-Grained Pure Magnesium and ZK60 Magnesium Alloy in Phosphate Buffered Saline Solution.

The magnesium alloy ZK60 is a promising candidate as a material for biodegradable implants. One of the most important factors for biodegradable implants is the modification of their corrosion behavior to match the requirements for the healing bone or tissue. The corrosion behavior can be influenced by different factors, among them the grain size, which can be changed by severe plastic deformation processes such as High Pressure Torsion Extrusion (HPTE).

Investigation of the stress reduction and temperature increase due to ultrasonic vibrations with different amplitudes during compression tests of steels with varying specimen sizes.

High-frequency vibrations in the ultrasonic range influence the plasticity of metals during metal forming: there is stress and force reduction during ultrasonic treatment compared to metal forming without ultrasound. Different reasons for this behavior are discussed: a combination of stress superposition, energy absorption in dislocations, temperature increase, and frictional changes. This investigation shows the influence of partially superimposed ultrasonic vibrations with amplitudes in the range of ∼ 1.

A Constitutive Relationship between Fatigue Limit and Microstructure in Nanostructured Bainitic Steels.

The recently developed nanobainitic steels show high strength as well as high ductility. Although this combination seems to be promising for fatigue design, fatigue properties of nanostructured bainitic steels are often surprisingly low. To improve the fatigue behavior, an understanding of the correlation between the nanobainitic microstructure and the fatigue limit is fundamental.