磁致伸缩Fe-Ga合金轧制薄板制备及性能

发布时间：2018-04-09 01:05

本文选题：磁致伸缩　切入点：Fe-Ga合金　出处：《北京科技大学》2016年博士论文

【摘要】：本文以实现大磁致伸缩Fe-Ga合金轧制薄板的制备为目标,对Fe-Ga合会的轧制变形和薄板热处理工艺进行了研究,以NbC第二相添加促进二次再结晶Goss{110}001织构的发展,探索出柱状晶板坯轧制加工制备薄板的方法,改善了合金的加工性能和薄板热处理织构,实现了类似单品生长的薄板制备,沿轧制方向的最大磁致伸缩性能超过280 ppm。研究了不同NbC添加量的定向凝固Fe83Ga17合金磁性能,对添加0.1 at%NbC的Fe-Ga合金的变形行为进行了研究,并通过引入柱状品改善了合金的加工性能。利用-步成型定向凝固技术,制备出不同NbC添加量的100取向合金,发现添加NbC可以改善定向凝固合金100取向度,添加微量0.1 at%的合会,第二相析出少,最大磁致伸缩在15 MPa预应力下可达335ppm,且饱和磁化场不显著增加。添加0.1at% NbC的Fe83Ga17合金,在变形温度超过400℃时,锻造多晶合金的压缩变形抗力随温度的升高而快速降低,对应锻造多晶热轧板静态拉伸抗拉强度也迅速降低,断裂延伸率则显著提高；定向凝固柱状品通过消除横向品界,可以显著提高合会沿变形方向的延伸率,避免轧制过程中的横向开裂,柱状晶试样及其热轧板拉伸断裂延伸率显著高于锻造多品合金及其热轧板。探索获得具有较优性能的Fe-Ga合金轧制薄板热处理工艺,研究了锻造多品Fe-Ga合金轧制薄板热处理过程中的再结晶行为,及热处理工艺对织构发展的影响。在850℃初次再结晶热处理过程中,丫织构先于{001}110形变织构形核发生再结晶,初次再结晶织构主要为Y织构。初次再结晶后,更高温度等温热处理不能发生有效的二次再结晶,而连续升温热处理可以促进二次再结晶Goss织构的发展。热处理过程中的升温速率显著影响二次再结晶织构及磁致伸缩性能,在0.25℃/min附近,可以形成较强的准确位向二次再结晶Goss织构。连续升温热处理后的高温热处理阶段,引入流动H2有利于消除第-：相析出,同时促进{110}晶粒的生长,并伴随磁致伸缩性能的提高。在热轧板坯中沿轧制方向引入定向凝固柱状晶制备轧制薄板,通过热处理工艺的控制,实现了高取向度大磁致伸缩Fe-Ga薄板的制备。柱状晶晶粒取向在形变和再结品过程中存在取向遗传性,同时,柱状晶的引入还可以显著提高薄片热处理过程中的二次再结晶。以0.1 at%NbC作为抑制剂,可以有效促进Goss品粒二次再结品,二次再结晶在连续升温(0.25℃/min)热处理过程中开始温度低于950℃。连续升温S气氛热处理,通过引入大量富S富Nb析出阻碍表面品界迁移,表面品粒细小且不易生长,高温Ar/H2热处理后,第二相析出和细小品粒完全消除,获得类似单品的强烈Goss取向,二次再结品Goss品粒尺寸达到厘米级,样品平均饱和磁致伸缩245±10 ppm,沿轧向不加压条件下的最大磁致伸缩超过280 ppm。在微偏离Goss取向Fe-Ga薄片表面,磁畴呈“柳叶刀”形貌,并排列成“梳状”,“柳叶刀”畴在磁场下的运动与磁致伸缩呈现显著的对应关系。
[Abstract]:In this paper, in order to achieve a large magnetostriction of Fe-Ga alloy rolling sheet was prepared as the goal, the rolling deformation and heat treatment process of Fe-Ga alloy sheet was studied, and promote the development of two Goss{110}001 NbC to the recrystallization texture of second phase addition, explore the method of columnar crystal slab rolling sheet fabrication, improve the alloy the processing performance and heat treatment of thin texture, to achieve a similar single product growth plate preparation, properties of directionally solidified Fe83Ga17 alloy magnetic maximum magnetostriction along the rolling direction of more than 280 ppm. of different amount of NbC, the deformation behavior of Fe-Ga alloy with 0.1 at%NbC were studied, and improve the processing performance of the alloy through the introduction of columnar products. By - step forming technology of directional solidification, prepared 100 orientation alloy with different NbC content, found that adding NbC can improve the directional solidification of alloy 100 orientation, The addition of trace 0.1 at% alloy, second phase precipitation, the maximum magnetostriction in up to 15 MPa prestressed under 335ppm, and saturated magnetic field does not increase significantly. The Fe83Ga17 alloy with 0.1at% NbC, the deformation at the temperature above 400 DEG C, forging alloy compression deformation rapidly decreased with increasing temperature and resistance. The forging of polycrystalline hot-rolled plate static tensile tensile strength decreased rapidly, the fracture elongation increased significantly; directional solidification columnar products by eliminating the transverse boundary, can significantly improve the extension will be along the direction of deformation rate, avoid transverse cracking in the rolling process, the columnar specimen and tensile fracture of hot rolled plate and the elongation rate significantly much higher than that of alloy products and hot rolled sheet rolling. Explore the heat treatment process of Fe-Ga alloy has a good performance, again by forging multi product Fe-Ga alloy rolling sheet during heat treatment The crystallization behavior, and the influence of heat treatment process on the recrystallization texture development. 850 degrees in the first heat treatment process, Ya texture prior to {001}110 texture nucleation of recrystallization, primary recrystallization texture is mainly Y texture. After primary recrystallization, high temperature heat treatment can effectively the two time crystallization, and continuous heat treatment can promote the development of the two Goss recrystallization texture. In the heat treatment process of heating rate significantly affected two times recrystallization texture and magnetostriction, near 0.25 degrees /min, can form a strong and accurate orientation two times recrystallization texture. Goss continuous rise high temperature after heat treatment the processing stage, the flow of H2 is conducive to the elimination of the phase precipitation, and the increase of {110} grain growth, and with the improvement of magnetostriction. In hot rolled slab along the rolling direction by directional solidification columnar crystal prepared by rolling The thin plates, controlled by heat treatment process, to achieve a high degree of orientation of giant magnetostrictive Fe-Ga thin plate. The preparation of columnar grain orientation on the deformation and recrystallization are orientation inherited, goods in the course of the introduction of columnar crystals can also significantly improve the sheet during heat treatment two times recrystallization. With 0.1 at%NbC as the inhibitor, can effectively promote the Goss grain two times again, two times of recrystallization during continuous heating (0.25 degrees /min) in the process of heat treatment temperature is lower than 950 DEG S. Continuous heating atmosphere heat treatment, through the introduction of a large number of rich S Nb rich precipitates hinder the migration table surface boundary, surface quality the grain is fine and not easy growth, high temperature after Ar/H2 heat treatment, the second phase precipitation and fine particle completely eliminated, similar strong orientation Goss single product, two times recrystallization grain size reached Goss centimeter, the average saturation magnetostriction 245 + 10 ppm, along the rolling direction without The maximum magnetostriction is more than 280 ppm. under the pressure condition, and the magnetic domain is "Lancet" morphology on the surface of Goss Fe-Ga thin slice. The magnetic field is arranged in "comb". The motion of the lancet domain in magnetic field is significantly corresponding to magnetostriction.

【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG335.5

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