摘要
在金属/气体共晶定向凝固工艺(Gasar)中,气体压力、过热度以及凝固速率是影响藕状多孔金属结构的最重要参数。建立了一个描述Gasar工艺过程的传热、传质、气孔形核、生长、合并及气孔与固相的协同生长的三维非稳态理论模型。并且采用有限差分的方式,实现了定向凝固铸造法Gasar工艺过程中藕状多孔结构形成及演变的计算机仿真,揭示了气体压力和凝固速率对藕状多孔金属最终结构参数的影响。基于Mg-H系的模拟与相应试验结果吻合较好,验证了所建仿真模型的合理性。
Gas pressure,overheat and solidification velocity are the most important parameters influencing the final structure of the lotus-type porous metal which is prepared by metal-gas eutectic directional solidification process（Gasar）.A three-dimensional time-dependent model was developed to describe the heat transfer,mass transfer,gas pore nucleation,growth and merging as well as synergistic growth with solid phase during the formation process of lotus-type porous structure.Corresponding computation program was developed to simulate the porous structure formation and evolution during Gasar solidification by using the finite difference methods to understand the influence of gas pressure and solidification velocity on porous structure of lotus-type metal.The simulated structural parameters such as average pore diameter and porosity of Mg-H system have a well agreement with the corresponding experimental ones,which reveals that the developed model is feasible in structural simulation of lotus-type porous metals.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2012年第1期37-41,共5页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金重点资助项目(u0837603)
民用航天十二五预研项目
中国空间研究院CAST创新基金资助项目
教育部回国人员科研启动基金资助项目
