Discontinuously reinforced intermetallic matrix composites via XD synthesis. [exothermal dispersion]
Discontinuously reinforced intermetallic matrix composites via XD synthesis. [exothermal dispersion]
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DOI：
10.1179/mst.1992.8.4.317
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发表时间：
1992-04
影响因子：
1.8
通讯作者：
K. Kumar;J. Whittenberger
中科院分区：
文献类型：
--
作者：
K. Kumar;J. Whittenberger
综述了XD工艺生产的非连续增强金属间化合物基复合材料的最新研究成果。研究的金属间化合物基体包括NiAl、多相NiAl+ Ni 2AlTi、CoAl、近γ钛铝化物（即TiAl+ Ti 3Al）和含有少量第二相的L12三铝化物。基质和增强材料的合理匹配可以提高物理和机械性能。颗粒增强物可以通过提高模量和强度直接影响性能，或者通过细化晶粒尺寸、提高铸件中的微观结构均匀性或提供改善相变动力学的额外成核位点间接影响性能。低温和高温强度，压缩和拉伸蠕变，弹性模量，环境延性和断裂韧性等力学性能进行了讨论，作为功能的钢筋尺寸，形状和体积分数。变形前后的显微组织进行了检查，并与测量性能。在许多系统检查的兴趣的观察是“分散弱化”在高温和高应变率。这种行为并不是XD工艺所特有的，在其他不连续复合材料中也有类似的观察结果。提出了这种行为的机制。MST/1561
A review is given of recent results obtained for discontinuously reinforced intermetallic matrix composites produced using the XD process. Intermetallic matrixes investigated include NiAl, multiphase NiAl+Ni2AlTi, CoAl, near γ titanium aluminides (i.e. TiAl+Ti3Al), and L12 trialuminides containing minor amounts of second phase. A judicious match of the matrix and reinforcement can enhance both physical and mechanical properties. Particulate reinforcements can affect properties directly by enhancing modulus and strength or indirectly by refining grain size, enhancing microstructural homogeneity in a casting, or providing additional nucleation sites which improve phase transformation kinetics. Such mechanical properties as low and high temperature strength, compressive and tensile creep, elastic modulus, ambient ductility, and fracture toughness are discussed as functions of reinforcement size, shape, and volume fraction. Microstructures before and after deformation are examined and correlated with measured properties. An observation of interest in many of the systems examined is ‘dispersion weakening’ at high temperatures and high strain rates. This behaviour is not specific to the XD process; rather similar observations have been reported in other discontinuous composites. Proposed mechanisms for this behaviour are presented. MST/1561