Papers by Keyword: Secondary Phase Particles

Abstract: Cold-rolling process is an important stage in Ti+P-IF steel manufacturing process, and cold rolling reduction is a main parameter. The research of recrystallization microstructure change and texture evolution of Ti+P-IF steel in cross cold rolling reductions has important meaning in study of high strong IF steel. In this paper, hot rolled Ti+P-IF steel in austenite was studied, cold rolling reduction was used as the effect factor, The study was carried out on the basis of microstructure observation, TEM analysis and texture measurement. The sizes of the grains within the recrystallization organizations were gradually diminished as the cold rolling reduction increased. At the same time, the second phase particles had showed an aggregated distribution, and there is a rule in the components of the texture that the Goss texture and the Rotating cube texture are transformed intoγtexture evolution rule.

Abstract: Microscale fatigue damage mechanisms in various Al-Sn-Si based bearing alloys used as linings of plain automotive bearings are reported. Extensive work on previously developed alloys has concluded that secondary phase particles such as Sn and Si are potential fatigue initiation sites with a complex combination of various particle geometry parameters. A newly developed alloy contains a number of complex widely scattered intermetallics with much finer and fewer Sn and Si particles. This alloy system appears to be more resistant to initiate microscale fatigue damage compared to the previous systems.

Abstract: The effects of the copper content on the bendability of Al-Mg-Si alloy T4 sheets were investigated. The Al-Mg-Si alloys with less than 0.01mass%Cu, 0.4mass%Cu and 0.8mass%Cu were prepared, and the time of solution heat treatment was changed to obtain different dispersion conditions of the second phase particles and to obtain different shear band formation conditions by bending. For the samples with less than 0.01mass%Cu and 0.4mass%Cu, no cracks were observed during the bending. For the sample with 0.8mass%Cu, the maximum depth of the crack by bending increased with the time of solution heat treatment up to 75 seconds, and then decreased over 75 seconds. The second phase particles decreased by increasing the solution heat treatment time, while the formation of shear bands by bending increased by increasing the solution heat treatment time and the copper content. The cause of the occurrence and the propagation of cracks by bending are considered to be the combined effect of the shear band formation across some grains and the micro-voids formed around the second phase particles. Improving of the bendability requires a decrease in the size and number of the second phase particles and/or reduced shear band formation during the bending.