铜-铝扩散焊及拉伸的分子动力学模拟

采用分子动力学方法模拟了铜-铝扩散焊过程，分析了理想平面铜-铝试件(001)晶面间扩散焊的过渡层厚度，并利用径向分布、键对分析方法分析了在不同的降温速率下过渡层的结构变化.降温速率大时，过渡层保持原有无序结构，降温速率小时，过渡层从无序结构向面心立方结构转变.还对扩散焊后的铜-铝试件进行了拉伸模拟，并与尺寸大小相近的单晶铜和单晶铝的拉伸模拟结果进行比较.结果发现焊接后的强度比单晶铝和单晶铜的强度都要小，最大应变值也小.

Molecular dynamics simulation of the diffusion bonding and tensile behavior of a Cu-Al interface

In this paper, we use molecular dynamics simulations to study the diffusion bonding of a Cu/Al interface. The interface analyzed is that between atomically smooth (001) crystalline planes of a Cu and an Al single crystals. The thickness of the transition layer of the bonded interface is obtained. The structural change of the interfacial region under different cooling rates is analyzed by means of the radial distribution function (RDF) and the pair analysis techniques. The interface assumes an amorphous structure upon initial mechanical pressing and remains amorphous if the subsequent cooling rate is high. At lower cooling rates, however, the interface structure becomes crystalline. The diffusion-bonded Cu/Al specimen is subjected to tensile loading and its strength is compared with those of single-crystalline Cu and single-crystalline Al of the same size along the same direction. Calculated results indicate that the specimen with the interface has a lower tensile strength and a lower ductility than the corresponding single-crystalline Cu and Al specimens.