應变时效处理鐵铝锰碳合金的相变態与超顺磁微结构之研究  

Study on the Phase Transformation and Superparamagnetic Nanostructures of Strained and Aged Fe-Al-Mn-C Alloys

作　　者：林英志 

机构地区：[1]高雄应用科技大学模具工程系

出　　处：《材料导报》2004年第8期114-118,共5页Materials Reports

摘　　要：本研究计划之目的,系探讨沃斯田铁面心立方结构之铁-9铝-30锰-1碳-0.5矽合金,两种试样时效热处理后内部微析出物显微结构与超顺磁性质之关系,两种试样分别为固溶油冷与固溶油冷锻应变20％～50％,再同时於823K持温140天时效处理。本研究结果显示:此种合金固溶油冷经冷锻应变再时效析出处理,可以显著地改善此种合金内部微结构磁性相析出物之导磁率与饱和磁化强度,其原因系归因於沃斯田铁相面心立方结构之铁铝锰碳合金,固溶处理,再经20％～50％之冷锻加工应变(变形)后,则在{111}八面体原子最密集结晶面之<110>原子最密集向量上,会引生叠差与可动差排密度量之增加,进而在沃斯田铁基地内部,增加叠差能与差排之相互作用,并促成差排核心铁/锰-碳偶合(Fe/Mn-C couples)的碳原子重新取向,所以应变与时效析出处理,能提升此种材料内部差排和其相关溶质原子之扩散与物理化学反应,进而提升时效处理后,合金内部之微结构磁性相析出物在非磁性基地的时效析出效果,并改善时效处理后,试样内部之微结构磁性相析出物之导磁率与饱和磁化强度。 X-ray绕射实验与穿透式电子显微镜(TEM)研究证实:微结构磁性相析出物系源自於层状k-相的相变能反应所产生之产物,而微结构磁性相析出物(B2+D0_3)与k-相之结晶方向关系为[112]_(B2+D0_3)+//[133]k;[300]_(B2+D0_3)//[400]_(B2+D0_3)//[011]k,及微结构磁性相析出物α′-Mn与B2之结晶方向关系为[001]_(α′-Mn)//[123]B_2。The object of the study was investigated the nanostructured precipitates and superparamagnetic properties of the γ-austenite face centered cubic (FCC) Fe-9Al-30Mn-lC-0. 5Si alloys,for which two kinds of specimens were solution-treated (S. T.) quenching in oil, and the S. T. quenching in oil then cold-forged 20%～50% strain,respectively. Both of the specimens were aged treatment at 823 K for 140 days. The experiment results reveal that the strained and aged treatment can improve the essenitial susceptibility and saturation magnetization of the alloy. The reason is ascribed to the S. T. and cold-forged strain that will induce to increase in the density of stacking fault as well as increase in the mobile dislocations on the close-packed {111} octahedral planes and in the<1 10> closepacked directions. This result leads to enhance the stacking fault energy interaction with dislocation and the reorientatin of carbon members of Fe/Mn-C couples in the cores of dislocations. Furthermore,the specimen after strained and aged treatment appears that the diffusion of physical and chemical reactions in the solute atoms and mobile dislocations will be promoted. Also,it is the strained and aged treatment that the nanoparticles of a ferromagnetic phase precipitated out of a nonmagnetic matrix can be elevated,and the susceptibility and satruation magnetization of the nanostructured precipitations in the alloys can then be improved.X-ray diffraction experiment and TEM study confirm that the nanostructured precipitates result from lamellar perovskite K-phase owing to a phase transformation. The crystal orientation relationships between the nanostructured (B2+D0_3)and κ-phase can be determined to be [1 12](b2+d0_3)//[T33]_(?); [300](b2+d0_3)//[400](b2+d0_3)//[011]_κ. The crystal orientation relationships between the nanostructured monoclinic a'-Mn and ordered B2 can be described as [001]_α-Mn//[123]B2.

关 键 词：铁铝锰碳合金 相变 应变时效 超顺磁性 微结构 

分 类 号：TG142[一般工业技术—材料科学与工程] TG111.5[金属学及工艺—金属材料]