CAJ | 학술논문

研究半固态TiB2增强Al?Mg合金复合材料浆料的流变性能,对半固态加工过程中的充型模拟是必需的.在一台Searle型流变仪的加热室内,将TiB2增强原位Al?Mg合金复合材料样品再熔化,随后将温度降低到半固态温度范围.为了复合材料的流变性能,进行三种不同的实验:稳态实验、连续冷却实验和等温实验.此外,从实验得到的滞回曲线证实了浆料的触变性.结果表明:当等温保持时,复合材料浆料显示假塑性和剪切变稀行为直到剪切速率达到1300 s?1;在更高剪切速率(>1300 s?1)下,它显示出剪切增稠趋势,这可能是由于不可变形的纳米TiB2颗粒的团聚引起的.通过剪切速率的间歇阶跃变化(剪切突变实验)也证实了浆料的假塑性行为.
연구반고태TiB2증강Al?Mg합금복합재료장료적류변성능,대반고태가공과정중적충형모의시필수적.재일태Searle형류변의적가열실내,장TiB2증강원위Al?Mg합금복합재료양품재용화,수후장온도강저도반고태온도범위.위료복합재료적류변성능,진행삼충불동적실험:은태실험、련속냉각실험화등온실험.차외,종실험득도적체회곡선증실료장료적촉변성.결과표명:당등온보지시,복합재료장료현시가소성화전절변희행위직도전절속솔체도1300 s?1;재경고전절속솔(>1300 s?1)하,타현시출전절증주추세,저가능시유우불가변형적납미TiB2과립적단취인기적.통과전절속솔적간헐계약변화(전절돌변실험)야증실료장료적가소성행위.
The rheological behavior of the semi-solid TiB2 reinforced Al?Mg alloy composite slurry was investigated, which is required for the mould filling simulations during the semi-solid processing. TiB2reinforced in-situ Al?Mg alloy composite samples were remelted and subsequently brought to the semi-solid temperature regime within the heating chamber of a Searle type rheometer. In order to understand the rheological behavior of composites, three different types of experiment were carried out, namely, steady state test, continuous cooling test and isothermal test. Apart from that, the thixotropic nature of the slurry was confirmed from the obtained hysteresis loops during the experimentation. The results indicate that when isothermally held, the composite slurry exhibits pseudo-plasticity and shows shear-thinning behavior up to the shear rate of 1300 s?1, and at higher shear rates (>1300 s?1), it shows a shear thickening tendency, which is probably due to the agglomeration of non-deformable nano-TiB2 particles. The pseudo-plastic behavior of the slurry was also estimated employing intermittent step changes of shear rate (shear jump test).