J. Mater. Sci. Technol. ›› 2006, Vol. 22 ›› Issue (03): 315-320.

• 论文 • 上一篇    下一篇

Microscopic Phase-field Simulation of Competition Mechanism Between L12 and D022 Structure in Ni-Cr-Al Alloy

褚忠   

  1. 西北工业大学
  • 收稿日期:2005-05-27 修回日期:2005-09-14 出版日期:2006-05-28 发布日期:2009-10-10
  • 通讯作者: 褚忠

Microscopic Phase-field Simulation of Competition Mechanism Between L12 and D022 Structure in Ni-Cr-Al Alloy

Zhong CHU, Zheng CHEN, Yongxin WANG, Yanli LU, Yongsheng LI   

  1. State Key Lab of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2005-05-27 Revised:2005-09-14 Online:2006-05-28 Published:2009-10-10
  • Contact: Zhong CHU

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摘要： 基于微观相场模型，模拟了不同沉淀温度条件下Ni-14.5at.%Cr-16.5at.%Al合金原子图像、序参数的演化过程，探明了L12结构与D022结构沉淀序列和机制对温度的响应关系。在1073K和1223K时，首先以等成分有序化＋失稳分解机制沉淀非化学计量比L12相，随后，D022相以失稳分解机制主要在L12相有序畴界上沉淀；非化学计量比L12相逐步转化为化学计量比L12相；1073K与1223K相比，1073K时两相生成的孕育期都较短，长大速度较快。1373K沉淀时，首先以非经典形核机制同时沉淀L12和D022相，D022相逐渐缩小直至消失，L12相可长大，最终形成单一L12相

关键词: Ni-Cr-Al, 微观相场, 沉淀, 序参数, 模拟

Abstract: Simulations are performed on temporal evolution of atom morphology and ordering parameters of Ni-14.5 Cr-16.5 Al alloy during early precipitation process at different temperatures based on microscopic phase-field theory; the relationship between precipitation sequence and mechanism of L12 and D022 structure and precipitation temperature are illuminated. The nonstoichiometric ordered L12 phases appear first with congruent ordering+spinodal decomposition mechanism which is then followed by precipitation of D022 phases at ordering domain boundaries of L12 phases by spinodal decomposition mechanism at 1073 K and 1223 K. The nonstoichiometric L12 phases transform to stoichiometric ordering phases gradually. The incubation period of L12 and D022 phases is shorter at 1073 K than that 1223 K, and growth speed is higher at 1073 K. At 1373 K, L12 and D022 phases appear simultaneously by non-classical nucleation and growth mechanism. After that the particles of D022 phases diminish and disappear gradually; L12 phases grow and single L12 phases are remained at last.

Key words: Ni-Cr-Al, Microscopic phase-field model, Precipitation, Ordering parameter, Simulation