中文摘要：

利用分子动力学软件LAMMPS模拟钛-铝扩散焊过程,分析700K,50 MPa时接触表面附近钛原子和铝原子扩散情况,并对不同冷却速率下的过渡层结构进行分析,发现过快的冷却速率导致过渡层结构的非晶化.同时,研究接触表面粗糙度对扩散的影响.结果表明：表面粗糙度是影响扩散过程的重要因素.对扩散后试样在不同应变率下进行拉伸测试,研究接头力学性能,发现高应变率下拉伸性能要好于低应变率下的拉伸性能,拉伸时,钛部分的变形机制为孪晶,铝部分的变形机制为滑移,接头屈服强度为相同尺寸单晶钛的62%左右,单晶铝的74%左右.

英文摘要：

Molecular dynamic software LAMMPS is used to simulate titanium-aluminium diffusive bond- ing process, the diffusion of their atoms at 100 K and under 50 MPa is analyzed, the structure of the tran- sient layer cooled with different rates is also analyzed, and it is found that excessive cooling rate would re- sult in an amorphous structure of the transient layer. Meantime, the effect of roughness of contact surface on the diffusion is investigated. The result shows that the surface roughness is an important influencing factor on the diffusion process. The tensile performance of bonding joint is examined with different strain rate and it is found that the tensile performance of the sample with higher strain rate will be better than that with lower strain rate. The deformation mechanism is also studied that twin boundaries can be identi- fied in Ti region and slip lines are found in A1 region. The yield strength of the bonding joint can reach 62% of monocrystalline Ti and 74% of monocrystalline A1 with the same size.