预退火对超微磁合金稳定性的影响

用动态ＤＳＣ方法研究了预退火对超微晶Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９稳定性的影响．经过预退火处理后与制备态相比可提高合金的晶化温度ＴＸ、放热峰值温度ＴＰ和晶化激活能θＫ，从而可提高超微晶合金的稳定性。经５１０℃预处理后合金的晶化激活能可由制备态的３８０ｋＪ／ｍｏｌ提高到５００ｋＪ／ｍｏｌ．     

超微晶合金的霍普金森效应研究

用霍普金森效应及Ｘ射线研究了铁基超微晶合金Ｆｅ７３．５Ｃｕ１Ｎｂ８Ｓｉ１８．５Ｂ９的居里温度和晶化过程。合金在５００℃退火１ｈ开始出现晶化相。随着退火温度的升高，晶化相的居里点由５００℃上升到５７０℃。同时，剩余非晶基体的居里点也发生变化。     

超微晶合金Fe73.5Cu1Nb3Si13.5B9晶化过程的X射线研究

用Ｘ射线衍射方法研究了超微晶合金Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９在退火过程中晶化相及晶格常数的变化。经４８０℃×１ｈ退火后，合金中出现ｂｃｃＦｅ（Ｓｉ）相，６００℃出现Ｆｅ３Ｂ相，６７０℃出现Ｆｅ２３Ｂ６相。退火温度升高时，Ｆｅ（Ｓｉ）相的晶格常数由０．２８３８ｎｍ上升到０．２８４９ｎｍ合金经过５５０℃×４ｈ退火后仍只有Ｆｅ（Ｓｉ）一个晶化相，其晶格常数随时间的变化不明显。     

FeCuNbSiB合金的纳米晶化过程研究

应用Ｘ射线衍射分析和穆斯堡尔谱学研究了Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９非晶合金的纳米晶化过程．Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金在５００～６００℃温度范围内分别退火１ｈ，可形成纳米ＤＯ３结构的ＦｅＳｉ相和剩余非晶相。随着退火温度的升高，有更多的ＦｅＳｉ相析出。在５００℃等温退火中ＦｅＣｕＮｂＳｉＢ合金出现二阶段纳米晶化过程。     

超微晶合金Fe_（73．5）Cu_1Nb_3Si_（13．5）B_9晶化过程的X

用Ｘ射线衍射方法研究了超微晶合金Ｆｅ７８．５Ｃｕ１Ｎｂ３Ｓｉ１８Ｂ９在退火过程中晶化相及晶格常数的变化。经４８０℃×１ｈ退火后，合金中出现ｂｃｃＦｅ（Ｓｉ）相，６００℃出现Ｆｅ３Ｂ相，６７０℃出现Ｆｅ２３Ｂ６相。退火温度升高时，Ｆｅ（Ｓｉ）相的晶格常数由０．２８３８ｎｍ上升到０．２８４９ｕｍ。合金经过５５０℃×４ｈ退火后仍只有Ｆｅ（Ｓｉ）一个晶化相，其晶格常数随时间的变化不明显。     

超微晶合金Fe73.5Cu1Nb3Si13.5B9晶化相的电镜观察及能谱分析

用透射电镜和能谱仪分析了Ｆｅ７３．５Ｃｕ１Ｎｂ３．Ｓｉ１３．５Ｂ９合金经不同温度退火后的组织，晶化相结构以及不同晶化相中的各元素含量变化，合金于４５０℃退火１ｈ析出尺寸小于５ｎｍ的ｂｃｃＦｅ（Ｓｉ）相，并且其尺寸随退火温度的升高而增大到约１５ｍｉｎ，于６００℃退火时合金中析了四方结构的Ｆｅ３Ｂ相，其晶格常数为ａ＝０．８７８ｎｍ，ｃ＝０．４３９ｎｍ在７００℃退火时出现面心立结构的Ｆｅ２３Ｂ６相，其晶     

Fe-Cu-Nb-Si-B纳米晶合金结构的Mssbauer谱研究

测定了Ｆｅ_（７３．５）Ｃｕ_１Ｎｂ_３Ｓｉ_（１３．５）Ｂ_９合金的单辊快淬制备态条带及其经热处理后的室温透射Ｍｓｓｂａｕｅｒ谱．制备态谱为典型非晶展宽六线谱，其内磁场平均值Ｈｉ＝１７．０１ＭＡ／ｍ．在Ｎ_２气氛保护下经４８０℃退火０．５ｈ已有明显结构弛豫或部分晶化发生；５３０℃退火１ｈ后样品已显著晶化，其主要组成为α－Ｆｅ（Ｓｉ）固溶体纳米晶和剩余非晶相，后者约占３９．１％，并随退火温度升高而减少，至６２０℃退火后约为２５％．非晶相的Ｈｉ值在结构弛豫阶段稍有上升，而在显著晶化温度以上则随温度升高而减小．在５５０℃退火样品中存在不同取向的体相磁织构．     

Fe-Cu-Nb-Si-B纳米晶合金结构的Mssbauer谱研究SCIEI

测定了Ｆｅ_（７３．５）Ｃｕ_１Ｎｂ_３Ｓｉ_（１３．５）Ｂ_９合金的单辊快淬制备态条带及其经热处理后的室温透射Ｍｓｓｂａｕｅｒ谱．制备态谱为典型非晶展宽六线谱，其内磁场平均值Ｈｉ＝１７．０１ＭＡ／ｍ．在Ｎ_２气氛保护下经４８０℃退火０．５ｈ已有明显结构弛豫或部分晶化发生；５３０℃退火１ｈ后样品已显著晶化，其主要组成为α－Ｆｅ（Ｓｉ）固溶体纳米晶和剩余非晶相，后者约占３９．１％，并随退火温度升高而减少，至６２０℃退火后约为２５％．非晶相的Ｈｉ值在结构弛豫阶段稍有上升，而在显著晶化温度以上则随温度升高而减小．在５５０℃退火样品中存在不同取向的体相磁织构．     

STRUCTURAL STUDY OF NANOCRYSTALLINE Fe-Cu-Nb-Si-B ALLOYS BY MSSBAUER SPECTROSCOPY

测定了Ｆｅ_（７３．５）Ｃｕ_１Ｎｂ_３Ｓｉ_（１３．５）Ｂ_９合金的单辊快淬制备态条带及其经热处理后的室温透射Ｍｓｓｂａｕｅｒ谱．制备态谱为典型非晶展宽六线谱，其内磁场平均值Ｈｉ＝１７．０１ＭＡ／ｍ．在Ｎ_２气氛保护下经４８０℃退火０．５ｈ已有明显结构弛豫或部分晶化发生；５３０℃退火１ｈ后样品已显著晶化，其主要组成为α－Ｆｅ（Ｓｉ）固溶体纳米晶和剩余非晶相，后者约占３９．１％，并随退火温度升高而减少，至６２０℃退火后约为２５％．非晶相的Ｈｉ值在结构弛豫阶段稍有上升，而在显著晶化温度以上则随温度升高而减小．在５５０℃退火样品中存在不同取向的体相磁织构．     

纳米晶Fe73.5Cu1Nb3Si13.5B9合金中缺陷及内应力的分布研究

用丰电子湮没技术和微观磁学方法研究了纳米晶Ｆｅ７３．５Ｃｕ１ｎｂ３Ｓｉ１３．５Ｂ９合金结构缺陷在退火过程中的变化规律，表明晶化初期形成的界面结构只引入少量的缺陷，晶化后期由于出现大量晶界，缺陷浓度急剧上升；非晶制备过程中以及晶化时引入的准位错偶极子造成的应力场对其软磁性能有很大的影响，并可以解释在最佳退火温度的磁性行为。     

CRYSTALLIZATION AND MAGNETIC PROPERTIES OF AMORPHOUS Nd_6Fe_(81)B_(13)ALLOY

The magnetic properties and the crystallization and its influence on the magnetic and struc-tural properties for rapidly quenched amorphous Nd_6Fe_(81)B-(13) alloy have been studied.The lowtemperature magnetic properties,the Curie temperature and the crystallization behavior arediscussed.A small addition(6at.-%)of Nd in amorphous Fe-B alloys increases largely thecrystallization temperature T_x but causes a decrease of the Curie temperature Tc·A newphase was observed in the sample annealed at 873 K.     

Effect of preannealing on crystallization process of amorphous Sm5Fe80Cu1Si5B3C2.5Zr3.5 alloy

In the view of crystallization activation energy of amorphous alloy,the mechanism of coarse grain in annealed Sm5Fe80Cu1Si5B3C2.5ZR3.5 amorphous alloy was analyzed.It reveals the e4ffect of preannealing on the process crystallization.The results show that preannealing can be used to change the crystallization behavior of the α-Fe phase in the Sm5Fe80Cu1Si5B3C2.5Zr3.5 amorphous alloy,whick is helpful for forming α-Fe phase grains;and it is not large for Sm2Fe17Cx phase.     

快速凝固粉末冶金Mg_(80)Cu_(10)Y_(10)合金的组织与力学性能

采用快速凝固粉末冶金技术制备热挤压Mg_(80)Cu_(10)Y_(10)合金棒材,研究了快速凝固Mg_(80)Cu_(10)Y_(10)合金薄带及热挤压后合金的相结构,并对热处理工艺对合金棒材组织结构及力学性能的影响进行了分析.研究表明,采用单辊快速凝固法在辊速为1800 r/min下制备的Mg_(80)Cu_(10)Y_(10)合金薄带为完全非晶态;在热挤压过程中Mg_(80)Cu_(10)Y_(10)合金中有Mg_2Cu和Mg晶体相析出,其显微硬度比薄带有所提高,这与合金中细小Mg_2Cu颗粒的弥散析出有关;在450 ℃保温4 h后的热挤压Mg_(80)Cu_(10)Y_(10)合金中没有新相析出;随着热处理温度的升高或保温时间的延长,由于Mg_2Cu颗粒出现重溶及聚集长大现象,使得热挤压Mg_(80)Cu_(10)Y_(10)合金的显微硬度表现出逐渐下降的变化趋势.     

Influence of heat treatment on the structure and magnetic properties of amorphous Co–Ni–Fe–Cr–Si–B alloy and its thermal stability

The causes of changes in the magnetic properties of an amorphous Co–Ni–Fe–Cr–Si–B alloy obtained by melt spinning in the form of a thin ribbon subjected to heat treatment and subsequent action of temperatures corresponding to various conditions of its exploitation have been analyzed. We have established the regimes of heat treatment that provide for the highest values of the maximum magnetic permeability of the alloy and the shielding factor of a magnetic shield made from the alloy. We have analyzed changes in the magnetic properties, shielding properties, and total magnetization distribution in an alloy ribbon at a temperature well below the crystallization temperature. We have found the temperature ranges that determine the practical application of this alloy.     

Effect of preannealing on glass transition and crystallization of gas atomized Cu47Ti33Zr11Ni8Si1 metallic glass powders

Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used as the main method to investigate the effect of relaxation on the glass transition and crystallization of Cu₄₇Ti₃₃Zr₁₁Ni₈Si₁ metallic glass powders. The preannealing treatments were performed at temperatures close to the experimentally determined glass transition temperature. It was found that the thermal stability is profoundly affected by preannealing since the crystallization temperature is strongly influenced by preannealing and decreases with increase in preannealing temperature. In contrast, the annealing treatment does not change the glass transition temperature. During heat treatment at temperatures around the calorimetric glass transition temperature, T_g, the glassy powder undergoes microstructural alterations as revealed by TEM but not discernible by XRD. Fine nanocrystals of about 4–6 nm homogeneously dispersed in an amorphous matrix are observed by TEM after annealing at 698 K for 60 min. Kissinger analysis reveals that the preannealing decreases the activation energy for nanocrystallization thereby promoting partial crystallization of the glass.     

Effect of heat treatment on structure and magnetic properties of Fe65.5Cr4Mo4Ga4P12C5B5.5 bulk amorphous alloy

This study deals with the Fe65.5Cr4Mo4Ga4P12C5B5.5 ferromagnetic bulk amorphous alloy. XRD analysis showed an amorphous structure of the as-cast sample. The same method revealed that, after annealing at 973 K for τ=10 min, the sample displayed a crystalline structure with crystalline phases formed. The crystallization process of the alloy was examined by DTA analysis. It was shown that crystallization took place in the temperature range between 810 K and 860 K with the exo-maximum peak temperature at 846 K with a heating rate of 20 K·min-1. The method also showed that, at temperatures ranging from 753 K to 810 K, the alloy exhibited the properties of supercooled liquids. A correlation between heat-induced structural changes and magnetic properties of the alloy was determined by thermomagnetic measurements. Maximum magnetization M=3.7 Am2·kg-1 of the alloy was reached after its annealing at 733 K for τ=10 min. Upon annealing, the alloy exhibited a relaxed amorphous structure. Annealing the alloy above the crystallization temperature led to a decrease in bulk magnetization. After annealing at 973 K for τ=10 min, the bulk magnetization of the alloy was M'=0.45 Am2·kg-1. Accordingly, after crystallization and formation of new compounds, the magnetization of the alloy was decreased by a factor of about 7.7. The strength of the magnetic field applied during the measurements was H=10 k A·m-1. The samples were tested for changes in the microstructure and hardness of both the amorphous phase and the resulting crystalline phase.     

等温热处理对Zr57Cu15．4Ni12．6Al10Nb5块体非晶合金的组织结构与压缩性能的影响

对Zr57Cu15．4Ni12．6Al10Nb5块体非晶合金进行了等温热处理，用X射线衍射仪、扫描电镜、显微硬度计与压缩试验机研究了不同温度下的等温热处理后合金的组织结构变化、硬度变化与压缩性能变化。该非晶合金出现晶化的温度随热处理时间的增长而降低。在热处理时间相同的条件下，随热处理温度升高，合金的显微硬度有增大趋势。当非晶合金出现相分离或晶化时，其抗压缩强度将急剧下降，断裂方式由非晶态的断裂方式向晶态的断裂方式转变。     

加压退火对 (La0.6Ce0.4)65Al10Cu25块体非晶合金晶化行为和热稳定性的影响

利用铜模铸造法制备了(La0.6Ce0.4)65Al10Cu25块体非晶合金,并在其过冷液相区内不同温度下,采用不同压力对该非晶合金进行加压退火处理,通过X射线衍射仪和差示扫描量热法研究了加压退火处理对该非晶合金晶化行为及热稳定性的影响。结果表明,加压退火促进了(La0.6Ce0.4)65Al10Cu25非晶合金的晶化过程,使得晶化初始温度Tx降低(dTx/dP=-5.17K/GPa),晶化激活能Ep随退火压力的增加而增大,并从能量和化学短程序畴的角度解释了加压退火对(La0.6Ce0.4)65Al10Cu25非晶合金晶化过程的影响机理。     

纳米晶(FeCo)78Nb6B15Cu1合金晶化过程及其磁特性研究

采用熔体快淬法制备(FeCo)78Nb6B15Cu1非晶薄带,通过DSC测试薄带的晶化特性,并据此在400,500,700和750℃进行1h退火处理。用XRD和SEM分析薄带在不同退火温度下的晶化行为,并用VSM测试薄带与粉体的静态磁参数。结果表明:对于固定成分的Hitperm合金,选择合适的退火温度,可控制晶粒大小和晶相比例。由于晶粒表面无序磁矩含量的变化,导致材料比饱和磁化强度发生变化,同时更小的纳米晶粒对降低矫顽力有利。由于淬态引入的微量结晶,薄带存在表面晶化现象,这在一定程度上会恶化材料的静态磁特性。     

Mg_(80)Cu_(15)Y_5合金的非晶形成能力及晶化行为

采用单辊快速凝同法制备出厚约40μm的Mg_(80)Cu_(15)Y_5非品合金薄带,利用XRD、DSC、TEM和HRTEM研究了非品合金的非品形成能力和晶化行为,分析了品化对合金组织结构与性能的影响.结果表明:Mg_(80)Cu_(15)Y_5合金的过冷液态温度区间△T_x和约化玻璃转变温度T_(rg)分别为55K和0.58,表明其具有较强的非晶形成能力;该合金在退火温度高于473 K后发牛明显晶化,从非品基体中析出 Mg_2Cu、Cu_2Y和Mg晶体相;随着退火温度的升高,合金的硬度呈现出先升高后降低的变化趋势,这与纳米品体相颗粒的弥散析出、重溶及粗化有关.