Mg_(65)Cu_(25)Y_(10)非晶态合金的形成及其晶化行为

采用水淬法制备出厚度为2mm的片状Mg65Cu25Y10非晶态合金,衡量其非晶成形能力的参数过冷液态区域宽度ΔTx(ΔTx=58.3K)、约化玻璃转变温度Trg(Trg=0.56)均较高,表明此合金具有很强的非晶形成能力;并测出了它的硬度为263.2HV。通过恒速升温和等温晶化试验,采用差热分析、X射线衍射等研究了它的热行为,结果表明,此合金在433K以下还是稳定的,如进一步升高温度,材料将由非晶态结构逐步向晶态结构转变,当退火温度达到623K时,则完全转变为晶态结构。

铒元素对锆基合金的非晶形成能力及力学性能的影响

以海绵锆为原料,采用水冷铜坩埚熔炼和铜模吸铸法制备了直径为3 mm、成分为(Zr_(0.55)Cu_(0.3)Al_(0.1)Ni_(0.05))_(100-x)Er_(x)(x=0,0.5,1,2,3,4,5)的锆基块体合金,通过对比不同铒含量海绵锆基合金的组织结构与性能,研究了铒元素对其非晶形成能力、热稳定性和力学性能的影响。结果表明:以海绵锆为原料时,锆基合金的非晶形成能力和力学性能明显下降。x=0时,无法制备成锆基非晶合金;添加Er元素后,海绵锆基合金的非晶形成能力和力学性能显著提高,具有非晶态结构;x=2时,海绵锆基非晶合金的力学性能最优,抗压强度σ_(bc)为 2142.5 MPa,室温下塑性应变 ε_(p)为 10.01%。与高纯锆制备的同直径(Zr_(0.55)Cu_(0.3)Al_(0.1)Ni_(0.05))_(98)Er_(2)非晶合金相比,其抗压强度恢复97.63%,室温塑性恢复 69.95%。添加铒元素有利于改善和提高海绵锆基合金的非晶形成能力和力学性能,为低成本制备锆基非晶合金提供一种新思路。

Design and characterization of biodegradable Mg-Zn-Ag metallic glasses

In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calculation of phase diagrams(CALPHAD)and experimental measurements.High GFA potentiality of two alloy series,specifically Mg_(96-x)Zn_xAg_(4)and Mg_(94-x)Zn_xAg_6(x=17,20,23,26,29,32,35),was predicted theoretically and then substantiated through experimental testing.X-ray diffraction(XRD)and differential scanning calorimetry(DSC)techniques were used to evaluate the crystallinity,GFA,and crystallization characteristics of these alloys.The results showed that compositions between Mg_(73)Zn_(23)Ag_(4)and Mg_(64)Zn_(32)Ag_(4)for Mg_(96-x)Zn_xAg_4,Mg_(66)Zn_(28)Ag_(6)and Mg_(63)Zn_(31)Ag_(6for)Mg_(94-x)Zn_xAg_(6)displayed a superior GFA.Notably,the GFA of the Mg_(96-x)Zn_xAg_(4)series was better than that of the Mg_(94-x)Zn_xAg_(6)series.Furthermore,the Mg_(70)Zn_(26)Ag_4,Mg_(74)Zn_(20)Ag_6,and Mg_(71)Zn_(23)Ag_(6)alloys showed acceptable corrosion rates,good cytocompatibility,and positive effects on cell proliferation.These characteristics make them suitable for applications in medical settings,potentially materials as biodegradable implants.

非晶合金的铸造工艺研究进展

随着科技手段的不断进步,材料的制备与研发朝着高性能的方向发展。目前,制造高性能新材料零件已经成为制造业的重要趋势,尤其是块体非晶合金零件的成形备受关注,成为当前研究的焦点和挑战。目前,研究比较广泛的非晶合金铸造成形技术包括真空压铸、真空吸铸、水冷铜坩埚感应熔炼铜模铸造等方法。探讨了工艺参数对玻璃成形能力(GFA)的影响,并列举了一些通过铸造成形方法制备的非晶合金零件及其精度。与传统晶体材料不同,非晶合金没有晶界、位错等缺陷,还分析了一些非晶合金常见的缺陷。非晶合金零件的成形能力和性能与基体金属的原料纯度密切相关,通过比较不同纯度的非晶合金,分析了原料纯度对零件性能的影响。目前,非晶合金铸造大多在真空或空气氛围下进行,研究了不同气氛对非晶合金铸造成形性能的影响。总的来说,非晶合金零件的成形制备技术在现代制造业中具有重要的应用前景。随着技术的不断发展,非晶合金零件的生产制造将会更加高效、精准,这为高端装备制造领域带来了更广阔的发展机遇。

Preparation and properties of novel Cu-based bulk metallic glasses Cu_(55-x)Zr_(37)Ti_8In_x

The glassy rods were successfully fabricated in the Cu-Zr-Ti-In alloy system by casting into a copper mold. The value of ATx reaches a maximum of 66 K for the BMG CusoZraTTi8In5 alloy. The reasons for enhancing glass forming ability of Cu-based BMGs with the addition of indium were discussed from atomic size and thermodynamics. Alternatively, the BMG Cu52Zra7Ti8In3 exhibits the highest compressive strength （1981 MPa） and the best plasticity among glassy Cu55-xZra7TisInx （x_〈5）. The total plastic deformation of Cu52Zr37TisIn3 before fracture approaches 1.2%.

Effect of minor Fe addition on glass forming ability and mechanical properties of Zr_(55)Al_(10)Ni_5Cu_(30) bulk metallic glass

A series of rod samples with diameter of 3 mm（Zr0.55Al0.10Ni0.05Cu0.30）100-xFex（x=0,1,2,3,4） were prepared by magnetic suspend melting and copper mold suction casting method.The effects of a small amount of Fe on glass forming ability（GFA） and mechanical properties of Zr55Al10Ni5Cu30 bulk metallic glass（BMG） were investigated.The results show that the addition of an appropriate amount（less than 3%,mole fraction） of Fe enhances GFA,as indicated by the increase in the reduced glass transition temperature Trg（=Tg/Tl） and the parameter γ（=Tx/（Tg＋Tl）） with increasing Fe content,and GFA gets deteriorated by further Fe addition（4%）.The addition of Fe also effectively improves the compressive plasticity and increases the compressive fracture strength in these Zr-based BMGs.Compressive tests on BMG sample with 3 mm in diameter and 6 mm in length reveal work-hardening and a certain plastic strain in the alloy containing 2% Fe.The BMG composite containing 4% Fe also exhibits a high fracture strength along with significant plasticity.

Effects of melt overheating degree on undercooling degree and amorphous forming of Nd_9Fe_(85-x)Ti_4C_2B_x(x=10, 12) magnetic alloys

The effectsof melt overheating degree on the undercooling degree and resultant solidification structures of Nd9Fe85-xTi4C2Bx（x=10, 12） glass-forming alloyswerestudied by differential thermal analysis combining with solidification structure analysis. The results indicate that the undercooling degree of Nd9Fe85-xTi4C2Bx（x=10, 12） alloys significantly increaseswith the rise of melt overheating degree, and two overheating degree thresholds corresponding to the drastic increase of the mean undercooling degree are found for each of the alloys. The existence of two turning points of the mean undercooling degreescan be linked to the structure transitions inside the overheated melts, which result in the evident increase of volume fraction of amorphous phasein the solidified structures.

Glass formation,thermal and mechanical properties of ZrCuAlNi bulk metallic glasses

The glass forming ability, thermal and mechanical properties of some Zr Cu Al Ni bulk metallic glasses were analyzed. The compositions of the alloys were theoretically determined with the dense packing and kinetic fragility index models. Cylindrical and conical ingots were produced by copper mould suction-casting under Ar atmosphere. The conical ingots were characterized by means of X-ray diffraction in order to determine the glassy structure. It was found that both alloys have a critical glassy diameter, Dc, of 3 mm. Thermal behaviours were investigated by differential scanning calorimetry at heating rates of 0.5, 0.67 and 0.83 K/s. The gamma parameter γ, supercooled liquid region ΔTx, and reduced glass transition temperature Trg, of the experimentally obtained glasses indicated high glass forming ability. The glassy compositions showed a fragility index of ~40 GPa. The compression test of the investigated alloys was carried out at a strain rate of 0.016 s^-1, obtaining a elastic modulus of ~83 GPa, total deformation of ~5%, yield strength of 1.6 GPa and hardness of 4 GPa. It was concluded that the use of the dense packing and kinetic fragility index models helped to predict glass-forming compositions in the family alloy investigated.

Glass formation and magnetic properties of Fe-based metallic glasses fabricated by low-purity industrial materials

Fe-based metallic glasses of(Fe74Nb6B20)100?xCrx(x=1,3,5)with high glass forming ability(GFA)and good magneticproperties were prepared using low-purity raw materials.Increasing Cr content does not significantly change glass transitiontemperature and onset crystallization temperature,while it enhances liquidus temperature.The addition of Cr improves the GFA ofthe(Fe74Nb6B20)100?xCrx glassy alloys compared to that in Cr-free Fe?Nb?B alloys,in which the supercooled liquid region(ΔTx),Trgandγare found to be50?54K,0.526?0.538,and0.367?0.371,respectively.The(Fe74Nb6B20)100?xCrx glassy alloys exhibit excellentsoft magnetic properties with high saturation magnetization of139?161A·m2/kg and low coercivity of30.24?58.9A/m.PresentFe?Nb?B?Cr glassy alloys exhibiting high GFA as well as excellent magnetic properties and low manufacturing cost make themsuitable for magnetic components for engineering application.

Bulk Glassy Alloys: Historical Development and Current Research

This paper reviews the development of current research in bulk glassy alloys by focusing on the trigger point for the synthesis of the first bulk glassy alloys by the conventional mold casting method. This review covers the background, discovery, characteristics, and applications of bulk glassy alloys, as well as recent topics regarding them. Applications of bulk glassy alloys have been expanding, particularly for Fe-based bulk glassy alloys, due to their unique properties, high glass-forming ability, and low cost. In the near future, the engineering importance of bulk glassy alloys is expected to increase steadily, and continuous interest in these novel metallic materials for basic science research is anticipated.

Alloying effects of the elements with a positive heat of mixing on the glass forming ability of Al-La-Ni amorphous alloys

The effects of Sn and Ga additions on the glass forming ability （GFA） of （A186LasNi9）100_xSnx（x=0, 0.2, 0.3, 0.5, 0.7, 1 and 2 at.%） and （Al86LasNi9）100_xGax（x=0, 0.2, 0.5, 1 and 1.5 at.%） alloys were systematically investigated. Unlike common microal- loying methods, both Sn and Ga have a positive heat of mixing with the main component of A1. Our analysis confirmed that proper Sn addition can suppress the strong formation of a-A1 and enhance the GFA due to the positive heat of mixing between Sn and AI and the large difference in their atomic sizes. While the addition of Ga to the base alloy acted as the nucleation cites for ct-Al and accelerated precipitation of the ct-A1 phase, thus deteriorating the GFA.

Fe-based bulk amorphous alloys with high glass formation ability and high saturation magnetization

It was well known that it was very difficult to prepare high performance Fe-based bulk amorphous alloys with both high Fe content and good glass-forming ability, especially for the Fe content （or total magnetic elements content） higher than 80 at%. In this paper, a series of Fe81-xCoxMO1P7.5C5.5B2Si3 （x = 0, 5, 10, 15, 20） bulk amorphous alloys （BAAs） with high saturation magnetization have been developed by copper mold casting method with fluxed ingot. It has been found that using Co replacing Fe in the Fe-Mo-P-C-B-Si alloy could significantly enhance the glass-forming ability and magnetic property. For the BAA with Co content of 0 at%, 5 at%, 10 at%, 15 at% and 20 at%, its saturation magnetization Js（Js=μoMs） was 1.55, 1.60, 1.62, 1.65 and 1.59 T, respectively. Among these alloys, the Fe66Co15- Mo1P7.5C5.5B2Si3 BAA exhibited a critical size of 2 mm in diameter and a high Js of 1.65 T. It suggested that these alloys with high magnetic element content possessed great potential in application due to their high glass-forming ability and high magnetic property.

Effects of Cu,Fe and Co addition on the glass-forming ability and mechanical properties of Zr-Al-Ni bulk metallic glasses

The thermal stability,glass-forming ability(GFA) and mechanical properties of Zr60Al15Ni25xTMx(TM = Cu,Fe and Co,x = 0-10) bulk metallic glasses(BMGs) were systematically investigated.Additional 5-10 at.% Cu greatly enhances the thermal stability and GFA of the base alloy.Zr60Al15Ni15Cu10 BMG exhibits the largest supercooled liquid region of 104 K and critical diameter of 18 mm.However,addition of 5-10 at.% Fe or Co decrease the thermal stability and GFA.In addition,the plasticity of the BMG can be improved by adding of Cu,while the strength is decreased slightly.Zr60Al15Ni20Cu5 BMG has the largest plastic strain of 5.5% with a yield stress of 1755 MPa and Young's modulus of 83 GPa.Addition of Co brings an increase of strength but a lower of plasticity,and additional Fe reduces the strength and plasticity simultaneously.

Ti-based glassy alloys in Ti-Cu-Zr-Sn system

Bulk amorphous formation in Ti-Cu-based multicomponent alloys, free of Ni, Pd and Be elements, were studied using the cluster-plus-glue-atom model. The basic cluster formula was revealed as [Ti9Cu6]Cu3 to explain the best binary glass forming composition Ti50Cu50=Ti9Cu9, where the CN14 rhombi-dodecahedron Ti9Cu6 was the principal cluster in the devitrification phase CuTi. This basic cluster formula was further alloyed with Zr and Sn and a critical glass forming ability was reached at （Ti7.2Zr1.8）（Cus.72Sn0.28） and （Ti7.2Zr1.8）（Cu8.45Sn0.55） up to 5 mm in diameter by suction casting, which was the largest in Ti-Cu- based and Ni-, Pd- and Be-free alloys.