The Porosity Evaluation during ECAP in Aluminium PM Alloy
The Porosity Evaluation during ECAP in Aluminium PM Alloy
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DOI：
10.12693/aphyspola.122.553
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发表时间：
2012-09
影响因子：
0.7
通讯作者：
J. Bidulská;T. Kvačkaj;R. Bidulský;M. Grande
中科院分区：
文献类型：
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作者：
J. Bidulská;T. Kvačkaj;R. Bidulský;M. Grande
本文的主要目的是显示在不同的工艺条件下，包括压制、烧结和等通道转角压力的应用过程中气孔率的变化。以铝基粉末(AlMgSiCuFe)为研究材料。施加不同的压制压力(400兆帕和600兆帕)后，在400◦C的通风炉中脱蜡60min。在610◦C的真空炉中烧结30min。试件采用单一等通道转角压力通道进行加工。粉末冶金加工方法的一个显著缺点是存在气孔。气孔起到了裂纹启动者的作用，由于它们的存在，横截面上的应力分布是不均匀的，从而导致有效承载面积的减小。等通道角压过程导致变形试件中的应力分布，使粉末颗粒挤压在一起，以至于最初相互连接的气孔转变为小的孤立气孔。提出的安全图包括等流道角压时应力和应变行为的综合影响。从力学观点来看，安全线消除并量化了作为潜在断裂起始点的大孔的影响
The main aim of this paper is to show porosity evolution during application of various processing conditions including pressing, sintering and equal channel angular pressure. An aluminium based powder (AlMgSiCuFe) was used as investigated material. After applying dierent pressing pressures (400 and 600 MPa), specimens were dewaxed in a ventilated furnace at 400◦C for 60 min. Sintering was carried out in a vacuum furnace at 610◦C for 30 min. The specimens were processed by single equal channel angular pressure pass. A signicant disadvantage of powder metallurgy processing methods is the presence of porosity. Pores act as crack initiators and, due to their presence, the distribution of stress is inhomogeneous across the cross-section and leads to reduction of the effective load bearing area. The equal channel angular pressure process, causing stress distribution in deformed specimens, made the powder particles to squeeze together to such an extent that the initially interconnected pores transform to small isolated pores. The proposed safety diagram includes the combined effect of stress and strain behaviour during equal channel angular pressure. The safety line eliminates and quanties the effect of large pores as a potential fracture initiation sites with respect to the mechanical viewpoint