Rheological behavior of semi-solid 7075 aluminum alloy at steady state

The further application of semi-solid processing lies in the in-depth fundamental study like rheological behavior. In this research, the apparent viscosity of the semi-solid slurry of 7075 alloy was measured using a Couette type viscometer. The effects of solid fraction and shearing rate on the apparent viscosity of this alloy were investigated under different processing conditions. It can be seen that the apparent viscosity increases with an increase in the solid fraction from 10% to 50%(temperature 620 oC to 630 oC) at steady state. When the solid fraction was fi xed, the apparent viscosity can be decreased by altering the shearing rate from 61.235 s-1 to 489.88 s-1 at steady state. An empirical equation that shows the effects of solid fraction and shearing rate on the apparent viscosity is fi tted:. The microstructure of quenched samples was examined to understand the alloy's rheological behavior.

面向骨科植入应用的可降解锌基材料研究进展

近几年来,锌合金凭借其良好的生物相容性、促成骨活性以及在体内无害降解等优势,展现出作为骨科内植物材料的巨大潜力。本文介绍了纯锌的生理作用、降解速率以及力学性能等方面的特性,以上述指标与骨科临床需求存在的差距为引,以合金化元素为分类依据,阐述了目前研究人员通过改变材料的微观组织结构并触发相应的强化机制,以及利用添加元素的生理协同功能等方式改善锌基材料性能的现有成果。对医用锌基材料领域在标准制定和合金设计改进以及引入增材制造等新技术等方面进行了讨论,以期匹配多样化的临床诊疗需求。