Fernández Daniel, Rodríguez-Prieto Alvaro, Camacho Ana María
Department of Manufacturing Engineering, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain.
Materials (Basel). 2021 Dec 9;14(24):7568. doi: 10.3390/ma14247568.
This paper investigates the effect that the selection of the die material generates on the extrusion process of bimetallic cylindrical billets combining a magnesium alloy core (AZ31B) and a titanium alloy sleeve (Ti6Al4V) of interest in aeronautical applications. A robust finite element model is developed to analyze the variation in the extrusion force, damage distribution, and wear using different die materials. The results show that die material is a key factor to be taken into account in multi-material extrusion processes. The die material selection can cause variations in the extrusion force from 8% up to 15%, changing the effect of the extrusion parameters, for example, optimum die semi-angle. Damage distribution in the extrudate is also affected by die material, mainly in the core. Lastly, die wear is the most affected parameter due to the different hardness of the materials, as well as due to the variations in the normal pressure and sliding velocity, finding critical values in the friction coefficient for which the die cannot be used for more than one forming stage because of the heavy wear suffered. These results can potentially be used to improve the efficiency of this kind of extrusion process and the quality of the extruded part that, along with the use of lightweight materials, can contribute to sustainable production approaches.
本文研究了模具材料的选择对双金属圆柱形坯料挤压过程的影响，该双金属坯料由航空应用中感兴趣的镁合金芯（AZ31B）和钛合金套筒（Ti6Al4V）组成。开发了一个稳健的有限元模型，以分析使用不同模具材料时挤压力、损伤分布和磨损的变化。结果表明，模具材料是多材料挤压过程中需要考虑的关键因素。模具材料的选择会导致挤压力变化8%至15%，改变挤压参数的影响，例如最佳模具半角。挤出物中的损伤分布也受模具材料影响，主要在芯部。最后，由于材料硬度不同以及法向压力和滑动速度的变化，模具磨损是受影响最大的参数，在摩擦系数中发现了临界值，由于模具遭受严重磨损，在一个以上的成型阶段不能使用该模具。这些结果有可能用于提高这种挤压工艺的效率和挤压件的质量，这与轻质材料的使用一起，有助于实现可持续生产方法。
