Surface Characteristics Improvement of AZ31B Magnesium by Surface Compositing with Carbon Nano-tubes through Friction Stir Processing

محورهای موضوعی : Mechanical Engineering

M. Soltani ¹ (Department of Materials Engineering, Isfahan University of Technology, Iran)
M. Shamanian ² (Department of Materials Engineering, Isfahan University of Technology, Iran)
B. Niroumand ³ (Department of Materials Engineering, Isfahan University of Technology, Iran)

تاریخ دریافت : 1393/08/07 تاریخ پذیرش : 1393/09/29 تاریخ انتشار : 1393/12/10

کلید واژه: Carbon Nano Tube (CNT), Friction Stir Processing (FSP), Surface Composite, Zener-Holloman Parameter,

چکیده مقاله :

In this research, the compositing of the surface of AZ31B magnesium alloy with CNT was studied by FSP. The parameters under study were rotational speed (500-1500 rpm), transverse speed (12-44 mm/min), number of passes (1-4), and CNT weight fraction (0-2%). Microhardness testing, optical metallography, FESEM, and EDS analysis were employed for the characterization of the samples. The suitable limits for the transverse speed and rotational speed were 12-24mm/min and 870-1140 rpm, respectively. The highest hardness in the FSP without compositing was assigned to the transverse speed of 24 mm/min and rotational speed of 870 rpm with a hardness of about 60 Vickers and the stir region grain size of less than 5 microns. The Zener-Holman parameter was calculated for computation and the least value was related to the conditions of the transverse speed of 12-24 mm/min and rotational speed of 870 rpm; as a result, the samples with the finest grain size were theoretically and experimentally specified. The most homogenous structure with the highest hardness was related to the three-pass state with a hardness of 69 Vickers. The best rate was the CNT weight percentage with a %2 weight enjoying the highest hardness. The FESEM images confirmed the suitable distribution of CNTs in the background after the performance of the three-pass processing.

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