Enhanced properties of Mg-based nano-composites reinforced with Al2O3 nano-particles
Enhanced properties of Mg-based nano-composites reinforced with Al2O3 nano-particles
复制标题
DOI：
10.1016/j.msea.2009.05.001
复制
发表时间：
2009-08-30
期刊：
影响因子：
6.4
通讯作者：
Poole, W. J.
中科院分区：
文献类型：
--
作者：
Habibnejad-Korayem, M.;Mahmudi, R.;Poole, W. J.
在本研究中，0.5、1和2 wt.%采用搅拌铸造法在纯镁和AZ 31镁合金中添加纳米氧化铝颗粒。平均粒径为100 nm的纳米Al 2 O3颗粒的均匀分布，细化了材料的晶粒组织，降低了材料的热膨胀系数，从而提高了纯镁和AZ 31合金的尺寸稳定性。添加2 wt.%纳米Al_2O_3颗粒在纯Mg中的CTE从27.9 × 10 ~（-6）K ~（-1）降低到25.9 × 10 ~（-6）K ~（-1），在AZ 31中的CTE从26.4 × 10 ~（-6）K ~（-1）降低到25.2 × 10 ~（-6）K ~（-1）方面显示出很大的潜力。对部分铸造试样进行热轧和退火处理，研究纳米颗粒对再结晶和后续力学性能行为的钉扎作用。力学性能的表征表明，纳米颗粒的存在下显着提高屈服应力和拉伸强度，但降低了纯镁和AZ 31的延展性。Mg-2Al（2）O（3）纳米复合材料的屈服应力和抗拉强度均提高了40 MPa，而AZ 31 -2Al（2）O（3）纳米复合材料的屈服应力和抗拉强度提高了约65 MPa。屈服强度的提高主要是由于基体和颗粒之间的CTE不匹配，较小程度上是由于Orowan和Hall-Petch强化机制。这些机制中的每一个的贡献被用于修改后的剪力滞模型来预测总复合材料增强实现。断口分析表明，纳米Al 2 O3颗粒的存在使整体材料的韧性断裂转变为脆性断裂。(C)2009 Elsevier B. V.保留所有权利。
In this study, 0.5, 1 and 2 wt.% of alumina nano-particles were added to pure Mg and AZ31 magnesium alloy via a stir-casting method. A uniform distribution of the Al2O3 nano-particles with an average diameter of 100nm, refined the grain structure of the cast materials and decreased the coefficient of thermal expansion (CTE), thus improving the dimensional stability of both pure magnesium and AZ31 alloy. The addition of 2 wt.% nano-Al2O3 particles showed great potential in the reduction of CTE from 27.9 to 25.9 x 10(-6) K-1 in pure Mg, and from 26.4 to 25.2 X 10(-6) K-1 in AZ31. Some of the cast samples were hot rolled and annealed to investigate the pinning effect of nano-particles on the recrystallization and subsequent mechanical property behavior. Characterization of mechanical properties revealed that the presence of nano-particles significantly increased yield stress and tensile strength but decreased the ductility of both pure magnesium and AZ31. The yield stress and tensile strength both increased by 40 MPa in the Mg-2Al(2)O(3) nano-composite, whereas this improvement was about 65 MPa for AZ31-2Al(2)O(3). The yield strength improvement was mostly due to the CTE mismatch between the matrix and the particles, and to a lesser extent to the Orowan and Hall-Petch strengthening mechanisms. The contribution of each of these mechanisms was used in a modified shear lag model to predict the total composite-strengthening achieved. Examination of fracture surfaces showed that the relatively ductile fracture of the monolithic materials changed to a more brittle mode due to the presence of nano-Al2O3 particles. (C) 2009 Elsevier B.V. All rights reserved.