(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 采用有限元方法和軸對(duì)稱單胞模型模擬了增強(qiáng)體(SiC)形狀、體積分?jǐn)?shù)以及不同基體類型對(duì)鋁基復(fù)合材料力學(xué)行為的影響。模擬結(jié)果表明：增強(qiáng)體的加入會(huì)阻礙基體的塑性流變，使基體內(nèi)發(fā)生非均勻變形，在增強(qiáng)體尖角處出現(xiàn)應(yīng)力集中；橢圓柱形增強(qiáng)體對(duì)基體塑性變形的阻力最大，傳遞載荷的能力最強(qiáng)，因此強(qiáng)化效果最好。在一定范圍內(nèi)，隨著增強(qiáng)體體積分?jǐn)?shù)的增加，基體與增強(qiáng)體之間的比表面積增大，有利于載荷的傳遞；增強(qiáng)體體積分?jǐn)?shù)的增加導(dǎo)致顆粒間距減小，幾何必須位錯(cuò)自由運(yùn)動(dòng)的路徑減少，復(fù)合材料的強(qiáng)度也隨之增加。此外，不同類型基體自身的塑性流變能力不同，Al-Zn-Mg基體強(qiáng)度最高，在拉伸變形過程中，受到增強(qiáng)體的阻礙作用最大，會(huì)有更多的載荷從基體傳遞到增強(qiáng)體，以Al-Zn-Mg為基體的復(fù)合材料的強(qiáng)度最高。
關(guān)鍵字: 復(fù)合材料；有限元模擬；力學(xué)行為
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The effects of reinforcement shape, volume fraction and matrix type on the mechanical behaviors of Al matrix composites were studied by finite element method based on the axisymmetric unit cell model. The simulation results show that the addition of reinforcement particles can inhibit plastic flow of the ductile matrix and result in non-uniform deformation of the matrix, with the stress concentration presenting around the particle corner. The truncated cylinder-shaped SiC particles have the maximum inhibition on the plastic flow of the ductile matrix and result in higher load transferring ability of the reinforcements. When the volume fraction of reinforcements is small, the interfacial area between the SiC particles and the matrix increases with the volume fraction of the SiC particles increasing, and thus more load can be transferred from the soft matrix to the hard SiC particles. At the same time, the dislocation strengthening effect increases with the decrease of the particle interspacing. Different types of Al matrixes have different flow abilities. During the tensile deformation process, the composite with Al-Zn-Mg matrix has the highest strength due to the higher strength of Al-Zn-Mg matrix and more load transferred from the matrix to the reinforcement.
Key words: composite; finite element simulation; mechanical behavior
