Processing, microstructural characterization and mechanical properties of a Ti2AlC/nanocrystalline Mg-matrix composite
Processing, microstructural characterization and mechanical properties of a Ti2AlC/nanocrystalline Mg-matrix composite
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DOI：
10.1016/j.compscitech.2008.11.007
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发表时间：
2009-03-01
影响因子：
9.1
通讯作者：
Barsoum, Michel W.
中科院分区：
文献类型：
--
作者：
Amini, Shahram;Ni, Chaoying;Barsoum, Michel W.
在这里，我们报告的处理和微观结构表征的50体积%。采用无压熔渗法在750 ℃保温1 h制备了Ti 2AlC/纳米晶Mg基复合材料。X射线衍射和透射电子显微镜都证实Mg晶粒尺寸类似于35 +/-15 nm。微观结构也非常稳定;在550 ℃下退火6 h不会改变Mg晶粒的尺寸。一些Mg溶解在Ti 2AlC中，证实存在（Ti 1-xMgx）（2）AlC固溶体，其中x高达0.2。少量Ti（3 +/- 1 at.%）也发现在镁矩阵。在350 - 40的极限拉伸强度是显着大于文献中报道的其他纯镁复合材料。在700 +/- 10 MPa下，这些复合材料的极限压缩应力比50体积%的复合材料的极限压缩应力高约40%。Ti 3SiC 2-Mg或50体积% SiC-Mg，其中Mg基体晶粒不是纳米级的。Ti 2AlC/nc-Mg复合材料易于加工，刚性（约70 GPa），强度高，重量轻（2.9 g/cm（3）），并表现出优异的阻尼能力，其随着施加应力的平方增加到约500 MPa的应力水平。在这样的应力水平下，每单位体积每循环耗散的能量被认为是结晶固体有史以来报道的最高能量，并且是由于初始扭结带的形成和湮灭。具有这样的固体的技术影响进行了简要讨论。(C)2008爱思唯尔有限公司保留所有权利。
Herein we report on the processing and microstructural characterization of 50 vol.% Ti2AlC/nanocrystalline (nc) Mg-matrix composites fabricated by pressureless melt infiltration at 750 degrees C for 1 h. X-ray diffraction and transmission electron microscopy both confirmed that the Mg grain size was similar to 35 +/- 15 nm. The microstructure was also exceptionally stable; annealing for 6 h at 550 degrees C did not alter the size of the Mg-grains. Some Mg was dissolved in the Ti2AlC confirming the existence of a (Ti1-xMgx)(2)AlC solid solution, with x as high as 0.2. A small amount of Ti (3 +/- 1 at.%) was also found in the Mg matrix. At 350 40 the ultimate tensile strength is significantly greater than other pure Mg composites reported in the literature. At 700 +/- 10 MPa, the ultimate compressive stresses of these composites were approximate to 40% higher than those of a 50 vol.% Ti3SiC2-Mg or a 50 vol.% SiC-Mg, in which the Mg-matrix grains were not at the nanoscale. The Ti2AlC/nc-Mg composites are readily machinable, stiff (approximate to 70 GPa), strong, light (2.9 g/cm(3)) and exhibited exceptional damping capabilities, that increased as the square of the applied stress to stress levels of the order of approximate to 500 MPa. The energy dissipated per cycle per unit volume at such stress levels is believed to be the highest ever reported for a crystalline solid and to be due to the formation and annihilation of incipient kink bands. The technological implications of having such solids are briefly discussed. (C) 2008 Elsevier Ltd. All rights reserved.