液淬条件对非晶态合金制备脆化和晶化的影响

研究了用单辊法制备非晶态合金条带时，冷却辊表面线速、熔体射流压力、喷射距离等参数对非晶态Ｆｅ３０Ｂ１１．４Ｓｉ３．５合金条带的形成、条带结构、性能及其退火脆化和晶化的影响。液淬工艺参数的合理配合下获得的足够高的液淬速率是得到非晶结构的关键，也是制备质量条带的决定因素。液淬速率愈高，条带厚度愈小，其脆化敏感性愈低。因此，高液淬速率下薄带的制备，有益于提高非晶态合金脆化抗力。非晶合金的晶化与液淬条件之间不存在直接的联系。     

非晶态合金研究进展

回顾了非是态合金的发展过程，讨论了其结构及性能特点，重点阐述了非晶态合金的磁性能及其应用，概述了非晶态合金研究的最新进展，展望了非晶合金的发展趋势。     

非晶态合金条带晶化温度的表面效应

通过示差扫描热卡计ＤＳＣ７的热焓测量，在连续升温的条件下研究了１０种非晶态合金条带的两个表面对晶化温度的影响。研究发现：非晶态条带的晶化开始和晶化峰顶温度对于条带的自由面和贴辊面是不相同的，其温度差值与非晶态条带的表面状态有直接关系。条带的两个面均光亮、平整，温差很小；表面粗糙的条带，两个面的晶化温度差较大。     

非晶态合金条带晶化温度的表面效应

通过示差扫描热卡计ＤＳＣ７的热焓测量，在连续升温的条件下研究了１０种非晶态合金条带的两个表面对晶化温度的影响，研究发现：非晶态条带的晶化开始和晶化峰顶温度对于条带的自由面和由辊面是不相同的，其温度差值与非晶态条的表面状态有直接关系，条带的两上面均光亮．平整，温差很小，表面粗糙的条带，两个面的晶化温度差较大。     

铁基非晶态合金防脆化方法研究EI

选用近共晶成分的合金和在合金中添加适量稀土元素Ｃｅ，以及用高液淬速率制备出超薄带，皆有益于降低铁基非晶合金退火脆化敏感性。用脉冲电流对铁基非晶条带进行快速加热退火，可在明显改善磁性的同时，使条带仍保持足够的变形能力；是实现铁基非晶合金磁性优化与良好延性配合的有效工艺。     

Fe-X-Ai-B非晶态合金强度和硬度

一、实验方法 3种非晶态材料分别为Fe_(72)Cr_5Si_(11)B_(12)、Fe_(73)Co_5Si_8B_(14)、Fe_(73)Ni_5Si_8B_(14),均采用熔体快淬单辊法制成宽1.40～2.03mm,厚30μm的带材。采用CRY—1型示差分析仪,测出3种非晶态合金的示差曲线,升温速率为10℃/mim,其结果见图1。T_M为弛豫峰温度,Tx_1,Tx_2分别为形成亚稳相Ⅰ,亚稳相Ⅱ的起始温度,具体数据见表。     

非晶态合金的应用概况

一、前言自从1981年5月第四届精密合金学术交流会以来,国内外在非晶态合金的应用方面都有长足的进步。此次四届会议之前,只有上海钢铁研究所鉴定了交通灯用非晶态合金。会后于1984年11月,上海钢铁研究所又鉴定了(7)项非晶态合金的应用,计有:(1)摄象管偏转聚焦线圈磁导筒用FC—12非晶态合金;(2)测速雷达电源变压器用非晶态合金;(3)Cu基中温焊料;(4)漏电开关用钴基FC—13非晶态合金;(5)电影机磁头用Co基非晶态合金;     

非晶态合金催化析氢阴极材料的研究进展

非晶态合金由于其优异的物理化学性能而备受研究者重视.特殊的空间结构使其表现出良好的化学活性,利用其亚稳态特性赋予电极材料特殊的化学性能,可将非晶态合金用于析氢电极材料.综述了非晶态合金阴极材料的研究进展,对过渡族金属元素的特性进行了分析,指出由过渡族金属元素组成的、具有低析氢超电势和低成本的非晶态合金复合镀层是目前与今后研究催化析氢电极材料的主要方向.     

非晶态合金的特性及其应用

简要介绍了非晶态合金的特性及其制备方法,以我国非晶态合金的应用状况为重点介绍了非晶态合金的应用。     

电沉积Ni-W非晶态合金复合镀层研究

研究了在Ni－W非晶态合金镀液中加入ZrO2纳米微粒后的电沉积工艺,得到工艺参数与非晶态复合镀层的成分、结构和镀层在面形貌的关系。加入ZrO2纳米微粒后,提高了Ni-W非晶态复合镀层的高温抗氧化性能和硬度。     

添加AlN对机械合金化Zr65Al7.5CU17.5Ni10非晶态合金热稳定性的影响

以成分为Zr65Al7.5Cu17.5Ni10的元素的粉末混合物及AIN颗粒为起始材料,经机械合金化形成非晶态合金为基体的复合材料,AIN添加量为5％－30％（体积分数,下同）,利用X射线衍射（XRD）,透射电子 显微镜（TEM）和差示扫描量热计（DSC）分析了含AIN复合材料的结构特性,玻璃转变与晶化行为,TEM观察表明,AIN第二相粒子弥散分布在晶Zr基合金基体上,粒子尺寸为20－200nm,仍为初始的晶体结构,与未添加AIN的Zr基非晶态合金相比,含5％－10％AIN的复合材料仍表现出较宽的过冷液态温度区域,玻璃转变温度（Tg)和晶化激活能（Ex)没有显著变化,但晶化起始温度（Tx)向高温移动大约10K,导致过冷液态温度区域的扩宽,AIN含量增至30％,明显的玻璃转变消失,Tx升高的20K。     

宽过冷液相区铁基非晶合金的形成和磁性

用熔体急冷法制备出具有明显的玻璃转变和较宽的过冷液相区的Fe-Co-(Nb)-Zr-B非晶合金,研究了热稳定性和软磁性能。结果表明,在Fe-Co-Zr-B四元合金中添加适量的Nb可以显著扩大过冷液相区,提高合金的热稳定性。当冷却速率降低时,急冷合金具有非晶和纳米晶的复相结构。非晶合金的饱和磁化强度随Nb含量的增加而减小。不同Nb含量的非晶合金的饱和磁致伸缩系数均较低。在低于晶化温度的温度下退火可以有效地降低矫顽力,改善软磁性能。晶化导致软磁性能降低。     

Fe61Co10Zr5W4B20块体非晶合金的形成及其力学性能

采用铜模吸铸法获得直径为2 mm的Fe61Co10Zr5W4B20块体非晶合金.采用X射线衍射、扫描电镜、示差扫描量热仪、微显硬度及压缩实验等研究了非晶合金的结构、热稳定性、显微硬度与压缩性能.结果表明:Mo的引入不利于非晶合金的形成;Fe61Co10Zr5W4B20块体非晶合金表现为二级晶化,玻璃转变温度为561.1℃,晶化起始温度为619.0℃,第一晶化峰值温度为632.6℃,第二晶化峰值温度为747.0℃,过冷液相区为57.9℃;该非晶合金的显微硬度为1207HV0.2,抗压强度σbc为1707.6 MPa.     

Glass-Forming Ability for Nd_(70-x)Fe_(20)Al_(10)Y_x and Nd_(60-x)Fe_(30)Al_(10)Y_x Alloys

The glass-forming ability (GFA) of Nd70-xFe2oAl10Yx and Nd60-xFe30Al10Yx (0< x <15) alloys produced by Cu mold casting was investigated. Except Y=5 at. pct, bulk amorphous Nd70-xFe20Al10Yx alloys up to 2 mm in diameter were obtained. The GFA for Nd60-xFe30Al10Yx alloys, however, was found to decrease with increase of Y due to the increasing compositional deviation from the original eutectic point of Nd60Fe30Al10 alloy. The Nd60Fe20Al10Y10 and Nd60Fe30Al10 alloy exhibit the largest GFA and can be cast into bulk amorphous cylindrical specimens of 3 mm in diameter. The melting temperature or/and the reduced crystallization temperature is closely related to the GFA of Y-containing alloys. The bulk amorphous cylinder for the Nd55Fe20Al10Y15 alloy shows a distinct glass transition temperature and a wide supercooled liquid region before crystallization. The crystallization temperature, Tg, and the supercooled liquid region, TX, are 776 K and 58 K, respectively. The GFA and thermal stability of the Nd-Fe-AI-Y a     

Glass-Forming Ability for Nd70-xFe20AlioYx and Nd60-xFe30Al10Yx Alloys

The glass-forming ability (FGA) of Nd70-xFe20Al10Yx and Nd60-xFe30Al10Yx(0≤x≤15) alloys produced by Cu mold casting was investigated.Except Y=5 at.pct,bulk amorphous Nd70-xFe20Al10Yx alloys up to 2mm in diameter were obtained.The GFA for Nd60-xFe30Al10Yx alloys,however,was found to decrease with increase of Y due to the increasing compositional deviation from the original eutectic point of Nd60Fe30Al10 alloy.The Nd60Fe20Al10Y10 and Nd60Fe30Al10 alloy exhibit the largest GFA and can be cast into bulk amorphous cylindrical specimens of 3mmm in diameter.The melting temperature or /and the reduced crystallization temperature is closely related to the GFA of Y-containing alloys.The bulk amorphous c ylinder for the Nd55Fe20Al10Y15 alloy shows a distinct glass transition temperature and a wide supercooled liquid region before crystallization.The crystallization temperature,Tg,and the supercooled liquid region,ΔTx,are 776K and 58K,respectively,The GFA and thermal stability of the Nd-Fe-Al-Y alloys were discussed.     

LASER INDUCED CRYSTALLIZATION OF AMORPHOUS Se80Te20 ALLOY THIN FILMS

The present study is concerned with the laser induced crystallization of amorphous thin films of Se₈₀Te₂₀ alloy. The films were prepared on a glass substrate by vacuum evaporation from bulk Se₈₀Te₂₀ alloy. The as-grown films were amorphous. The crystallization induced by an argon ion laser irradiation was studied at different beam intensities ranging from 50 mW to 600 mW and different time durations. The 486 nm (blue green) line was chosen for irradiation. The crystallization and growth processes in the laser irradiated samples were studied in the electron microscope at low temperature (173 K). it was seen that the crystallization was quicker at higher laser beam intensities as expected. The conditions for the onset of nucleation and the progress of crystallization in these films are compared with those observed in the films irradiated by electron beam.     

碳纳米管对Fe-P非晶的力学性能和晶化行为影响的研究

采用快速凝固技术制备了碳纳米管／铁碳非晶复合材料,并对其组织、力学性能和热稳定性进行了研究检测结果表明,碳纳米管在非晶基体中的弥散存在,使得非晶抗拉强度提高,晶化激活能增加,晶化特征温度明显提高,加入２Ｗ／％碳纳米管,使铁磷非晶的室温抗拉强度提高了１２０％,晶化激活能增加了约４０％,晶化开始温度提高了约１００Ｋ,此外,在温度高于其晶化温度约２００Ｋ时,碳纳米管和非晶基体界面间发生了固相反应。     

Deformation behavior of a TiZr-based metallic glass composite containing dendrites in the supercooled liquid region

The deformation behavior of a TiZr-based bulk metallic glass composite(BMGC) was characterized in the supercooled liquid region(SLR) from 623 K to 693 K. It was observed that the alloy exhibits the deformation behavior from work softening at low temperatures to work hardening at high temperatures.The yield stress and overshoot stress decrease remarkably with the increase of temperature, accompanied by superplasticity. The results showed that the crystallization occurred in the amorphous matrix for the post-deformation samples and the volume fraction of the corresponding crystallization products increased with increasing testing temperature. It is implied that the work hardening behavior was closely associated with the crystallization of the amorphous matrix. The tensile stress can accelerate the crystallization of amorphous matrix and the martensitic transformation of dendrite phases, which implies that the thermal stability of the alloy decreases under tension. These findings shed light on designing new BMGCs with high mechanical performance as well as the good SLR formability.     

Fabrication of bulk amorphous Fe67Co9.5Nd3Dy0.5B20 alloy by hot extrusion of ribbon and study of the magnetic properties

We report on the preparation of bulk amorphous Fe₆₇Co_9.5Nd₃Dy_0.5B₂₀ by hot extrusion of melt-spun ribbons. X-ray diffraction studies were performed to check the structure of the as-spun ribbons and the consolidated bulk specimens. Differential scanning calorimetry (DSC) analysis of the amorphous ribbons revealed that crystallization proceeds in two stages. The first crystallization step leads to the formation of soft magnetic α-(FeCo) and (FeCo)₃B and the second crystallization step corresponds to the formation of the hard magnetic (NdDy)₂(FeCo)₁₄B phase. The hysteresis loop of the as-spun ribbon reveals soft magnetic properties which change to hard magnetic behavior with enhanced remanence after annealing at 973 K for 7 min. X-ray diffraction analysis proves the presence of both soft and hard magnetic phases in the annealed sample. The viscosity of the powder obtained from crushed ribbons was investigated by parallel plate rheometry, showing a distinct viscosity drop in the supercooled liquid region that allows for easy consolidation of the crushed ribbons. The hot extruded sample that was subsequently annealed at 973 K for 7 min exhibits good hard magnetic properties with coercivity H_c = 218 kA/m, saturation magnetization J_s = 1.36 T, maximum energy product (BH)_max = 91.3 kJ/m³ and remanence B_r = 1.18 T (after demagnetization field correction), respectively.     

High formability of glass plus fcc-Al phases in rapidly solidified Al-based multicomponent alloy

A multicomponent Al₈₄Y₉Ni₄Co_1.5Fe_0.5Pd₁ alloy was found to keep a mixed glassy + Al phases in the relatively large ribbon thickness range up to about 200 μm for the melt-spun ribbon and in the diameter range up to about 1100 μm for the wedge-shaped cone rod prepared by injection copper mold casting. The glassy phase in the Al-based alloy has a unique crystallization process of glass transition, followed by supercooled liquid region, fcc-Al + glass, and then Al + Al₃Y + Al₉ (Co, Fe)₂ + unknown phase. It is also noticed that the primary precipitation phase from supercooled liquid is composed of an Al phase instead of coexistent Al + compound phases, being different from the crystallization mode from supercooled liquid for ordinary Al-based glassy alloys. In addition, it is noticed that the mixed Al and glassy phases are extended in a wide heating temperature range of 588–703 K, which is favorable for the development of high-strength nanostructure Al-based bulk alloys obtained by warm extrusion of mixed Al + amorphous phases. The Vickers hardness is about 415 for the glassy phase and increases significantly to about 580 for the mixed Al and glassy phases. The knowledge of forming Al + glassy phases with high hardness in the wide solidification and annealing conditions through high stability up to complete crystallization for the multicomponent alloy is promising for future development of a high-strength Al-based bulk alloy.