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电磁场与TiB2纳米粒子作用下CuAlMn形状记忆合金晶粒细化技术研究

Solidification in Electromagnetic Field of TiB2-Doped Shape-Memory CuAlMn-Alloy:A Methodological Study

  • 摘要: 使用扫描电子显微镜和光学显微镜研究了电磁场与TiB2纳米粒子作用下CuAlMn形状记忆合金的晶粒细化机理。结果表明:TiB2纳米粒子与CuAlMn形状记忆合金基体的最小二维错配度是5.28%,因此,TiB2纳米粒子可以作为CuAlMn形状记忆合金的有效异质形核核心显著细化其晶粒组织。电磁场能够有效抑制TiB2纳米粒子的团聚,提高TiB2纳米粒子的晶粒细化效果并能减少球形孔洞缺陷。添加1%TiB2纳米粒子的同时施加120 A的旋转电磁场,可以将CuAlMn形状记忆合金真空熔铸铸锭的晶粒组织从1.62细化至0.41 mm。

     

    Abstract: Liquid CuAlMn shape-memory alloy,doped with TiB2-nanoparticles,was solidified in rotating electromagnetic(EM) field for grain refinement. The influence of the TiB2-addition and rotating EM field on the grain-size was investigated with scanning electron microscopy.The results show that TiB2- nanoparticles and EM field had a major impact.Specifically,the uniformly distributed TiB2-nanoparticles acted as the heterogeneous nucleation seeds,because the minimum 2 D disregistry was calculated to be 5.28%; the dual-effect of TiB2- particles,nucleation-seed and pinning of grain-boundary,explained the grain-size reduction in low overcooling-degree of solidification.Besides,the rotating EM field effectively suppressed the agglomeration of TiB2-nanoparticles and prevented formation of spherical stomata defects.The addition of TiB2- 1.0%(wt) and EM field(generated by coil-current of 120 A) decreased the average grain-size to 0.41 mm,much smaller than that solidified without EM field and without TiB2- nanoparticles.

     

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