Sensitivity analysis for thickness uniformity of Al coating layer in extrusion of Mg/Al clad bar

Abstract

Although Mg alloys possess many attractive properties, the use of Mg alloys has been limited due to their extremely poor corrosion resistance. In the authors' previous study, they have developed a new process for Mg/Al cladding by hot extrusion with a convex die. In the extrusion process, it was found that the thickness uniformity of the Al coating layer can be controlled by changing the die angle.However, the optimal condition of the extrusion and the influences of extrusion parameters on the coating thickness uniformity remain unclear. In this study, therefore, the sensitivity analysis has been performed in order to evaluate the influences of extrusion parameters on the coating thickness uniformity.The sensitivities of the following five parameters were evaluated; (1) initial thickness of the coating material plate, (2) extrusion temperature, (3) ram speed, (4) die angle and (5) ratio of simulated flow stress to the experimental one for pure Al. In order to perform the sensitivity analysis, the process for Mg/Al cladding was modelled. The results from the extrusion model fairly agree with the experimental results. Thus, it can be said that the present model of Mg/Al cladding process is reliable. From the sensitivity analysis, it was found that the initial thickness of the coating material plate and die angle influence on the uniformity most. The extrusion temperature, ram speed and flow stress ratio do not have significant influences.

Coating on Magnesium Alloy with Super Duralumin by Hot Extrusion and Evaluation of Its Surface Properties

“…The thickness of the coating layer was 200 to 300 μm when AZ80 alloy was similarly coated with the pure Al using the Al plate of 3 mm in the initial thickness in the present authors previous study 2) . The difference in coating thickness between the present and previous studies is considered to be due to the initial thickness of the coating material, since a sensitivity analysis has revealed that the initial thickness of the coating material strongly affects the coating thickness of the extruded clad bar 8) . However, it is also considered that the difference in the coating thickness is affected by the difference in the deform-ability of the coating material.…”

Effect of the Shape of Rolling Passes and the Temperature on the Corrosion Protection of the Mg/Al Bimetallic Bars

“…Many works on the production of such layers on multi-layered plates, sheets, and round bimetallic Mg/Al bars can be found in the technical literature. The most commonly used methods include diffusion bonding [14,15], hot pressing [16,17], extrusion [18,19], rolling [20,21] and rolling in grooves [22,23], explosive welding [24,25], forging [26,27], and two-roll casting [28]. Additionally, in this case, some of the mentioned methods do not guarantee the right quality of the joint, the required thickness of the plating layer, and, in addition, in the case of round bimetallic bars, even distribution of the plating layer around the core perimeter [29,30].…”

“…Additionally, in this case, some of the mentioned methods do not guarantee the right quality of the joint, the required thickness of the plating layer, and, in addition, in the case of round bimetallic bars, even distribution of the plating layer around the core perimeter [29,30]. The most frequently used methods to produce round bimetallic bars include extrusion [18,19,31] and rolling in grooves [23,30,32]. The feedstock for these processes is made directly in the processes themselves, as in the case of extrusion [18,19] or with the possibility of earlier use of the casting method [22] or explosive welding [30,32].…”

Parameter Optimization of Amalgamated Al<sub>2</sub>O<sub>3</sub>-40% TiO<sub>2</sub> Atmospheric Plasma Spray Coating on SS304 Substrate Using TLBO Algorithm

“…A fuzzy logic model is offered to predict the surface hardness of TiN coating on AL7075-T6 with respect to changes in input process parameters, Direct Current (DC) power, DC bias voltage, and nitrogen flow rate. Toko et al [6] performed the sensitivity analysis in the process for Mg/Al cladding model in order to evaluate the influences of extrusion parameters on the coating thickness uniformity. The sensitivities of initial thickness of the coating material plate, extrusion temperature, ram speed, die angle, and ratio of simulated flow stress to the experimental one for pure Al were evaluated.…”