铜—铝两相材料固液成型的分子动力学模拟

发布时间：2018-11-07 17:19

【摘要】：本文利用分子动力学模拟方法,模拟了固-液复合法制取铜铝复合材料的过程,研究了保温时间对复合材料过渡层厚度的调控作用、不同过渡层厚度的铜铝复合材料在拉伸载荷下的力学性能,并分析了过渡层形成的细节及过渡层对力学性能的影响。研究表明,在升温和降温条件一致的情况下,过渡层厚度明显受保温时间的影响,随着保温时间变长,过渡层增厚,且增幅变缓。过渡层厚度对材料力学性能也有显著影响,当材料过渡层厚度增加的时候,材料的杨氏模量、弹性极限、屈服极限及强度极限都相应的降低,且降幅变缓。铜铝在固液复合过程中,由于铜原子处于固态,铝原子处于液态,铝原子相对于铜原子处于高活性状态,相互扩散主要是以铜原子脱离固态与铝原子充分熔合为主,其次是少量铝原子进入固态铜中间进行熔合。过渡层主要是由金属间化合物及原子团组成,它们的存在是降低材料强度的主要因素。过渡层变厚时,相应的金属间化合物种类及数量均变多,其无序性也变得复杂,这些因素都大大降低了金属键的完整性。
[Abstract]:In this paper, molecular dynamics simulation method is used to simulate the process of preparing Cu-Al composite by solid-liquid composite method, and the effect of holding time on the thickness of transition layer of the composite is studied. The mechanical properties of copper-aluminum composites with different thickness of transition layer under tensile loading were analyzed. The details of the formation of transition layer and the influence of transition layer on mechanical properties were analyzed. The results show that the thickness of the transition layer is obviously affected by the holding time under the same temperature and cooling conditions. With the increase of the holding time, the thickness of the transition layer increases, and the increase of the transition layer becomes slower. When the thickness of the transition layer increases, the Young's modulus, the elastic limit, the yield limit and the strength limit of the material will decrease, and the decrease will be slower. In the solid-liquid recombination process, the copper atom is in the solid state, the aluminum atom is in the liquid state, the aluminum atom is in the highly active state relative to the copper atom, the main diffusion is that the copper atom is separated from the solid state and fully fused with the aluminum atom. Secondly, a small amount of aluminum atoms are fused into the solid copper. The transition layer is mainly composed of intermetallic compounds and atomic groups, their existence is the main factor to reduce the strength of the materials. When the transition layer is thicker, the variety and quantity of intermetallic compounds increase, and the disorder becomes more complex. These factors greatly reduce the integrity of metal bond.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB331

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