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Effect of Shot Peening on Surface Characteristics and Fatigue Properties of T5-treated ZK60 Alloy
(2009)
Ti-90Al (in at.%) coatings were deposited on Ti-45Al-8Nb alloy at two different temperatures, 300 and 540 °C. The coatingsputtered at 300 °C consisted of Al and TiAl3 with columnar grain structure. The morphology, chemical composition and microstructureof the coating sputtered at540 °Cwere strongly dependent on the substrate microstructure. The two coating variantsformed oxidation-resistant Al2O3 scales during oxidation. The special morphological features of the coatings make them interestingfor geometrically structuring the surfaces to provoke the lotus effect.
Tensile and high cycle fatigue (HCF) properties of the hot-rolled Mg-12Gd-3Y (wt.%) magnesium alloyhave been investigated. The magnesium alloy exhibits a fatigue strength of about 150 MPa, which ismuch higher than that of the commercial Mg-8Al-Zn alloy AZ80. Aging heat-treatment (T5) improvedthe fatigue life of the Mg-12Gd-3Y alloy. Fatigue cracks nucleated at the intense slip bands in theas-rolled alloy. After T5 treatment, however, the fatigue crack nucleation site shifted to the phase boundariesbetween MgGdY particles and Mg matrix. T5 heat-treatment retarded the crack initiation and thusimproved the fatigue life of the Mg-12Gd-3Y alloy.
Wenngleich der Verwendung von Mg-Knetlegierungen im Automobilbau ein großes Potenzial zugesprochen wird, ist deren Einsatz bislang von geringer Bedeutung geblieben. Im Rahmen des vom BMBF-geförderten Verbundforschungsvorhabens "MIA-Magnesium im Automobilbau" wurden daher in Zusammenarbeit der Firmen DaimlerChrysler AG, ThyssenKrupp Umformtechnik GmbH, Otto Fuchs Metallwerke KG, Honsel GmbH & Co. KG, GP Innovation GmbH, OSK Kiefer GmbH sowie der BTU Cottbus die Grundlagen für die prototypische Fertigung von Bauteilen aus den Mg-Knetlegierungen des Typs AZ31 und AZ 80 erarbeitet.