Ag和Fe元素添加对Cu-Zr-Al系非晶形成能力和力学性能的影响

以Cu-Zr-Al三元系为基础,研究Ag和Fe合金组元添加对块体金属玻璃(BMG)及BMG基复合材料的非晶形成能力和力学性能的影响.在Cu-Zr-Al三元合金体系中,Cu50Zr42Al8系BMG的△Tx=61 K,Trg=0.624,γ=0.416.适量添加Ag元素能显著地提高非晶形成能力:在Cu-Zr-Al-Ag四元合金体系中,Cu43Zr45Al8Ag4、Cu45Zr42Al8Ag5、Cu40Zr44Al10Ag6、Cu43Zr41Al8A98和Cu36Zr48Al8Ag8的Trg分别为0.618、0.625、0.618、0.628和0.598,γ值分别为0.424、0.427、0.424、0.432和0.433,△TX分别为77、76、78、84和108 K.在(Cu0.36Zr0.48-Al0.08Ag0.08)100-XFex(x-=0,3,5,10,15,20)五元体系中,Fe的添加明显影响合金的非晶形成能力;尽管△TX和Trg呈下降趋势,但(Cu0.36Zr0.48Al0.08Ag0.08)97Fe3块体非晶合金仍具有较高的非晶形成能力,其△TX=103 K,Trg=566,γ=0.424:Fe的适量加入可显著提高合金的力学性能,其中(Cu0.36Zr0.48Al0.08Ag0.08)95Fe5合金的强度和塑性应变分别提高至2 249 MPa和4.9%.Fe元素的存在导致Cu36Zr48Al8Ag8合金中产生明显的相分离,使(Cu0.36Zr0.48Al0.08Ag0.08)100-xFex合金得到增强增韧.     

新型块体非晶合金Cu43Zr43Al7Pd7的形成能力及力学性能和腐蚀性能研究

利用铜模吸铸法成功制备了直径达5mm的新型块体非晶合金Cu43Zr43A17Pd7.利用XRD,DSC,DTA研究了该台金的非晶形成能力(GFA)和热稳定性.结果表明,Cu43Zr43A17Pd7表现出较好的非晶形成能力,表征非晶形成能力的参数Trg和分别为0.61和0.417,过冷液相区△Tx达75K.单轴压缩实验和SEM断口观察表明,该合金具有良好的力学性能,材料压缩断裂应变量和断裂强度分别达到4.9%和1876MPa.利用动电位极化研究了该非晶合金在1mol/L H2SO4和3%NaCl溶液中的电化学腐蚀行为.结果表明,非晶合金在这两种腐蚀介质中均存在自钝化现象,并形成较宽的稳定钝化区,钝化嚣电流密度在10-6-10-5 A/cm2间,远低于Cr18-Ni8不锈钢,表现出良好的耐蚀性能.     

ZrCuAlSi大块非晶合金形成及力学性能

通过铜模铸造法制备(Zr47Cu44Al9)100-xSix(x=0,0.5,1.5,2.5)大块非晶合金.利用差热分析、X射线衍射、显微硬度和室温压缩试验.研究分析添加Si元素对Zr47Cu44Al9合金非晶形成能力、热稳定性及力学性能的影响.结果表明,适量Si的加入能显著提高非晶合金的热稳定性,当Si的加入量为1.5时,合金具有最大的非晶形成能力,其纯非晶试样的临界尺寸由Zr47Cu44Al9的4 mm增大到(Zr47Cu44Al9)98.5Si1.5的6 mm.Si提高非晶形成能力的原因主要是抑制了引起异质形核的CuZr相的形成与析出.力学性能实验显示,显微硬度(Hv)随Si的加入由Zr47Cu44Al9合金的5850MPa增呔到(Zr47Cu44Al9)98.5Si1.5合金的6220 MPa,(Zr47Cu44Al9)98.5Si1.5合金的断裂强度为1862 MPa.     

Co元素对Ti-Zr-Be-Cu块体非晶合金力学性能的影响

采用铜模铸造法制备了Ti35Zr30Be27.5-xCu7.5Cox(x=0,3.5,7.5,11.5)系列块体非晶合金。采用X射线衍射仪(XRD)、万能试验机和扫描电镜(SEM)研究了Co元素添加对Ti-Zr基非晶合金力学性能的影响。结果表明,Co元素适量替代Be元素有利于提高该非晶合金的塑性。当Co含量(摩尔分数)为3.5%时,Ti35Zr30Be24Cu7.5Co3.5块体非晶合金具有最高的断裂强度及塑性应变,分别为2 196MPa和4%;Co含量为7.5%时,非晶合金断裂强度、塑性应变均迅速降低,分别为2 062 MPa和1.5%;进一步增加Co含量至11.5%时,合金的断裂强度又提高到2 106 MPa,而塑性应变仅为0.2%。     

Co对Ti-Zr-Be-Cu块体非晶形成能力及热稳定性的影响

采用铜型铸造法制备直径为12mm的Ti35Zr30Be27.5-xCu7.5Cox(x=3.5,7.5,11.5)系列块体非晶合金。采用X射线分析(XRD)、差示扫描量热仪(DSC)研究了Co元素含量变化对Ti-Zr基合金的非晶形成能力、结构变化以及热稳定性的影响。结果表明,随着Co元素替代部分Be元素(x=3.5,7.5),合金的非晶形成能力由5mm显著提高到12mm,进一步增加Co元素含量(x=11.5)时,非晶形成能力迅速降低,其形成能力不足5mm;但随着Co含量的变化,Ti35Zr30Be27.5-x Cu7.5Cox(x=3.5,7.5,11.5)系列块体非晶合金的玻璃转变温度Tg、晶化温度Tx分别从x=0时的636K和718K降低到x=11.5时的612K和647K。讨论了Co元素的添加对Ti35Zr30Be27.5-xCu7.5Cox(x=3.5,7.5,11.5)合金结构变化的影响。     

锆基大块非晶合金在NaCl溶液中的腐蚀行为

利用电化学方法研究了3种锆基大块非晶合金Zr60Al15Ni25、Zr65Al10Ni10Cu15和Zr52.5Al10Ni10Cu15Be12.5在1%、3.5%和10%（wt.%）NaCl溶液中的腐蚀行为.极化曲线的测试结果表明,在相同浓度NaCl溶液中Zr60Al15Ni25合金表面形成相对稳定的钝化膜,表现出较好的耐腐蚀能力.元素Cu和Be的添加,降低了合金Zr52.5Al10Ni10Cu15Be12.5和Zr65Al10Ni10Cu15在NaCl溶液中的钝化能力,增加了点蚀的敏感性.失重法研究结果表明3种合金腐蚀速率的大小顺序依次为Zr65Al10Ni10Cu15〉Zr52.5Al10Ni10Cu15Be12.5〉Zr60Al15Ni25.利用扫描电镜（SEM）和能量散射X射线谱（EDS）分析了极化后的合金表面,结果表明点蚀孔内部Zr、Al、Ni的选择性溶解和Cu在钝化膜下的富集导致了合金的耐腐蚀性能降低.     

添加微量Fe对Zr_(55)Al_(10)Ni_5Cu_(30)块体金属玻璃非晶形成能力和力学性能的影响(英文)

通过磁悬浮熔炼和铜模吸铸法制备直径3mm的(Zr0.55Al0.10Ni0.05Cu0.30)100-xFex(x=0,1,2,3,4)合金试样,研究Fe元素的微量添加对Zr55Al10Ni5Cu30块体金属玻璃非晶形成能力和力学性能的影响。研究表明,合理添加Fe元素(不超过3%,摩尔分数)导致约化玻璃转变温度Trg(=Tg/Tl)和参数γ(=Tx/(Tg+Tl))增大,因而其非晶形成能力增大,但添加过量的Fe元素(4%)会导致其非晶形成能力的降低。添加Fe元素也会显著地改善Zr55Al10Ni5Cu30块体金属玻璃的压缩塑性及提高其压缩断裂强度,当Fe元素的添加量为2%时,直径3mm、长度6mm的试样在压缩时出现一定的塑性及加工硬化现象。Fe元素添加量为4%形成的金属玻璃基复合材料,同样也显示良好的压缩塑性和高的压缩断裂强度。     

摩擦焊焊接块体非晶合金Zr65Cu12.5Al7.5Ni15

采用传统摩擦焊焊接方法连接具有良好非晶形成能力的Zr65Cu12.5Al7.5Ni15(at%)块体非晶合金.微区X射线衍射结果显示,整个焊接接头保持了非晶特性,无晶化反应发生.对摩擦焊焊接方法成功连接块体非晶合金Zr65Cu12.5Al7.5Ni15的原因进行了分析.     

Zr55Al10Cu30Ni5非晶合金在NaOH溶液中的腐蚀行为

利用极化曲线方法、电化学阻抗技术和扫描电子显微镜研究了非晶合金Zr55Al10Cu30Ni5在NaOH溶液中的腐蚀行为。极化曲线测试表明，非晶合金Zr55Al10Cu30Ni5在NaOH溶液中具有很好的耐蚀性能，阴极过程由电化学反应所控制，而阳极过程表现出钝化特征，在所研究的浓度范围内，钝化电流密度非常低，为1μA／cm^2～2μA／cm^2。电化学阻抗测试表明，电荷转移电阻随浓度的增大而增大，而后又有所降低。在阴极极化、开路电位和钝化电位下，非晶合金的Nyquist图由单容抗弧构成，具有很高的电荷转移电阻，表现出优良的耐蚀性。SEM和EDAX表明非晶合金在NaOH溶液中腐蚀轻微，各合金元素的溶解程度不同，腐蚀后表面出现了少量的氧元素。     

共格沉淀析出过程的微观结构演化相场法模拟

用铜模吸铸法制备了Zr(65-x)Cu17.5Ni10Al7.5Fex(x=0,1,2,3,4,5,at％)块体合金,利用X射线衍射仪(XRD)、透射电镜(TEM)、同步热分析(DSC)、万能试验机和扫描电镜(SEM)研究了Fe对Zr基合金的非晶形成能力、热稳定性及力学性能的影响.结果表明:适量添加Fe元素有利于提高该合金的非晶形成能力和热稳定性,当Fe含量为x=2时,其内部结构为完全非晶结构,并且此成分具有较高的GFA和热稳定性(△Tx=58 K).Fe元素的适量加入也有利于提高该合金的强度和塑性,其中x=2的块体非晶合金的抗压强度σf、断裂应变εf和塑性应变εp分别高达2338 MPa、12.4％和2.0％.     

Mg-Cu-Ni-Gd非晶合金结构弛豫及力学性能

采用差示扫描热分析仪(DSC/DTA),X射线衍射(XRD)和透射电镜(TEM)研究了Mg-Cu-Ni-Gd系非晶合金的结构弛豫以及力学性能,分析了Ni元素对Mg基非晶合金的结构弛豫和力学性能的影响.结果表明, Mg65Cu25 Gd10非晶合金在305 K下保温180 s发生结构弛豫后,出现约1-2 nm的中程有序畴.采用Ni元素部分取代Cu元素,可提高合金抗结构弛豫能力和力学性能.     

Fe- and Co-based bulk glassy alloys with ultrahigh strength of over 4000 MPa

Since the first synthesis of Fe-based bulk glassy alloys in Fe–(Al,Ga)–(P,C,B,Si) system in 1995, a number of Fe- and Co-based bulk glassy alloys have been developed up to date because their alloys are expected to exhibit high mechanical strength and good soft magnetic properties. The maximum diameter of Fe- and Co-based bulk glassy alloys exhibiting high fracture strength of over 4000 MPa is 5 mm for Fe–Co–B–Si–Nb system and 3 mm for Co–Fe–Ta–B–Mo–Si system. The addition of a small amount of Nb or Ta is essential for the increase in their glass-forming ability through the formation of network-like atomic configurations. The primary crystalline phase from supercooled liquid is a metastable complex FCC Fe₂₃B₆ or Co₂₃B₆ phase and hence the change to the local atomic configurations leading to the precipitation of the metastable Fe₂₃B₆ or Co₂₃B₆-type phase is thought to play an important role in the achievement of high glass-forming ability. The highest fracture strength reached as high as 4250 MPa for Fe–Co–B–Si–Nb alloy and 5545 MPa for Co–Fe–Ta–B–Mo alloy. The fracture strength has a good linear relation with Young's modulus, glass transition temperature or liquidus temperature. It is, therefore, concluded that the origin for the ultrahigh strength is attributed to the strong bonding nature among the constituent elements. Considering that Fe–Si–B amorphous alloy wires developed for several years between 1979 and 1983 have been used as high strength materials for the last two decades, the newly developed high-strength Fe- and Co-based bulk glassy alloys are expected to be used as a new type of ultrahigh strength material by utilizing the advantage points of much higher strength and three-dimensional material form.     

Effects of alloying elements on glass formation,mechanical and soft-magnetic properties of Fe-based metallic glasses

Effects of alloying additions on glass formation, mechanical and soft-magnetic properties of Fe-(Si,P,C,B)-based bulk metallic glasses (BMGs) were systemically studied in detail. It was found that the glass-forming ability (GFA) and the optimum doping content strongly depend on the electronegativity of the alloying elements, which are discussed in terms of liquid phase stability and crystallization resistance of the competing crystalline phases. These BMGs exhibit high fracture strength ranging from 2800 to 3800 MPa, which closely relates to the atomic size distribution in the alloys. Furthermore, appropriate additions of Co, Ga and Cu could improve not only the GFA but also the saturation magnetization due to different coupling mechanisms.     

Fe-Co-B-Si-Nb-Cr软磁块体非晶合金的制备及性能

采用微合金化技术,用铜模铸造法制备Fe-Co-B-Si-Nb-Cr块体非晶合金。借助于XRD、TEM、DSC、DTA和VSM表征该玻璃合金系的玻璃形成能力和软磁性能;借助动电位极化、宏观压缩试验和纳米压痕技术测试该玻璃合金系的腐蚀和力学性能。结果表明:Cr元素的加入,尽管稍微降低了Fe-Co-B-Si-Nb玻璃合金的形成能力,但却明显改善了它的软磁性能、力学性能和腐蚀性能;用铜模铸造法,可获得最大直径为4mm的玻璃棒;这些块体非晶表现出高饱和磁感应强度(0.81～1.04T)、极低的矫顽力(0.6～1.6A/m)、200～215GPa的杨氏模量、约2%的弹性应变和0.7%的塑性应变,还拥有超高的断裂强度(3840～4043MPa);用深度敏感纳米压痕技术研究了{[(Fe0.6Co0.4)0.75B0.2Si0.05]0.96-Nb0.04}96Cr4块体非晶合金的室温塑性变形;该合金的纳米压痕变形行为与加载速率有关:在0.75～3mN/s加载速率下,发现了显著的锯齿流变;当增大到6mN/s时,锯齿流变逐渐消失。另外,当Cr含量(原子分数%,下同)从x=0增加到x=4时,该块体非晶合金在0.5mol/LNaCl...     

Ta，b和MoTi50Ni20Cu25Sn5非晶合金玻璃形成能力的影响

利用旋转铜辊急冷法和铜模铸造法制备非晶合金薄带或圆棒，并采用X衍射仪(XRD)、差示扫描量热仪(DSC)和差示热分析仪(DTA)研究了Ta，Nb和Mo对Ti50Ni20Cu25Sn5非晶合金玻璃形成能力(GFA)的影响。结果表明，Ta的添加提高了Ti50Ni20Cu25Sn5合金的GFA，Mo的添加降低了该合金的GFA，Nb的添加剂对该合金的GFA没有明显的影响；含Ta合金具有超过60K的宽过冷液态区(△Tx)，且其约化玻璃转变温度因子(Tg／Tm)大于含Nb合金和含Mo合金；采用常规铜模铸造法制备出了直径为lmm的(Ti0.5Ni0.2Cu0.25Sn0.05)98Ta2和(Ti0.5Ni0.2Cu0.5Sn0.05)96Ta4块状非晶圆棒；(Ti0.5Ni0.2Cu0.25Sn0.05)98Ta2块状非晶圆棒的Tg，△Tx和Tg／Tm分别为678K，84K和0．60，而(Ti0.5Ni0.2Cu0.25Sn0.05)96Ta4块状非晶圆棒的Tg，△Tx和Tg／Tm分别为680K，70K和0．60。     

Glass formation and properties of Ti-based bulk metallic glasses as potential biomaterials with Nb additions

Ti_(47)Cu_(38-x)Zr_(7.5)Fe_(2.5)Sn_2Si_1Ag_2Nb_x (x=0, 1,2; at%) bulk metallic glasses (BMGs) with superior biocorrosion resistance were synthesized by copper mold casting. Although the minor addition of Nb to the Ti-CuZr-Fe-Sn-Si-Ag BMG slightly decreases the glass-forming ability (GF A), the Nb-bearing Ti-based alloys could be casted in a bulk glassy rod form with diameters up to3 mm. It is found that partial substitution of Cu with Nb is effective on enhancing the bio-corrosion resistance of the Ti-based BMG. Potentiodynamic polarization measurements show that Nb addition to Ti-based BMG leads to higher open-circuit potential and pitting potential as well as lower passive current density in Hank's solution. Electrochemical impedance spectroscopy (EIS) results indicate that with Nb content increasing, the charge transfer resistance values of the Ti-based BMGs become larger,demonstrating that the surface oxide films are more protective. The Nb-bearing Ti-based BMGs also exhibit good in vitro biocompatibility comparable to that of Ti-6Al-4V alloy. The enhanced bio-corrosion resistance, excellent in vitro biocompatibility and good mechanical properties of the Nb-bearing Ti-based BMGs are favorable for biomedical applications.     

Misch metal based metallic glasses

In this paper, a glass-forming range of metallic glasses based on Ce-rich misch metal (Mm) was pinpointed in Mm-Al-Co composition map by melt spinning. The thermal analysis indicated that the wide supercooled liquid region (above 60 K) can be found out in a large composition range in Mm-Al-Co system. The investigation of the glass-forming ability (GFA) in this system indicated a glassy composition with a larger supercooled liquid region wouldn’t be the glassy former with higher GFA. The reduced glass transition temperature is a better indicator to explore metallic glasses with high GFA. Furthermore, the mechanical properties of Mm₆₅Al₁₀Co₂₅ bulk glassy samples were evaluated in a compressive measurement. The obvious advantages of the Mm-based BMGs with high GFA, good mechanical properties and low material cost make these BMGs hopeful to be applied in the future.     

Effects of rare-earth elements on the glass-forming ability and mechanical properties of Cu46Zr47-xAl7Mx (M = Ce, Pr, Tb, and Gd) bulk metallic glasses

Cu46Zr47-xAl7Mx(M = Ce,Pr,Tb,and Gd) bulk metallic glassy(BMG) alloys were prepared by copper-mold vacuum suction casting.The effects of rare-earth elements on the glass-forming ability(GFA),thermal stability,and mechanical properties of Cu46Zr47-xAl7Mx were investigated.The GFA of Cu46Zr47-xAl7Mx(M = Ce,Pr) alloys is dependent on the content of Ce and Pr,and the optimal content is 4.at %.Cu46Zr47-xAl7Tbx(x = 2,4,and 5) amorphous alloys with a diameter of 5 mm can be prepared.The GFA of Cu46Zr47-xAl7Gdx(x = 2,4,and 5) increases with increasing Gd.Tx and Tp of all decrease.Tg is dependent on the rare-earth element and its content.△Tx for most of these alloys decreases except the Cu46Zr42Al7Gd5 alloy.The activation energies △Eg,△Ex,and △Ep for the Cu46Zr42Al7Gd5 BMG alloy with Kissinger equations are 340.7,211.3,and 211.3 kJ/mol,respectively.These values with Ozawa equations are 334.8,210.3,and 210.3 kJ/mol,respectively.The Cu46Zr45Al7Tb2 alloy presents the highest microhardness,Hv 590,while the Cu46Zr43Al7Pr4 alloy presents the least,Hv 479.The compressive strength(σc.f.) of the Cu46Zr43Al7Gd4 BMG alloy is higher than that of the Cu46Zr43Al7Tb4 BMG alloy.     

High-Entropy Metallic Glasses

The high-entropy alloys are defined as solid-solution alloys containing five or more than five principal elements in equal or near-equal atomic percent. The concept of high mixing entropy introduces a new way for developing advanced metallic materials with unique physical and mechanical properties that cannot be achieved by the conventional microalloying approach based on only a single base element. The metallic glass (MG) is the metallic alloy rapidly quenched from the liquid state, and at room temperature it still shows an amorphous liquid-like structure. Bulk MGs represent a particular class of amorphous alloys usually with three or more than three components but based on a single principal element such as Zr, Cu, Ce, and Fe. These materials are very attractive for applications because of their excellent mechanical properties such as ultrahigh (near theoretical) strength, wear resistance, and hardness, and physical properties such as soft magnetic properties. In this article, we review the formation and properties of a series of high-mixing-entropy bulk MGs based on multiple major elements. It is found that the strategy and route for development of the high-entropy alloys can be applied to the development of the MGs with excellent glass-forming ability. The high-mixing-entropy bulk MGs are then loosely defined as metallic glassy alloys containing five or more than five elements in equal or near-equal atomic percent, which have relatively high mixing entropy compared with the conventional MGs based on a single principal element. The formation mechanism, especially the role of the mixing entropy in the formation of the high-entropy MGs, is discussed. The unique physical, mechanical, chemical, and biomedical properties of the high-entropy MGs in comparison with the conventional metallic alloys are introduced. We show that the high-mixing-entropy MGs, along the formation idea and strategy of the high-entropy alloys and based on multiple major elements, might provide a novel approach in search for new MG-forming systems with significances in scientific studies and potential applications.     

Formation,ductile deformation behavior and soft-magnetic properties of (Fe,Co,Ni)–B–Si–Nb bulk glassy alloys

Fe-based [(Fe,Co,Ni)_0.75B_0.2Si_0.05]₉₆Nb₄ bulk ferromagnetic glassy alloy rods with the diameters up to 4 mm were synthesized by copper mold casting. The addition of Ni element caused no decrease in glass-forming ability and fracture strength, but increased the compressive deformation ductility of this Fe-based bulk glassy alloy system. The glassy alloy rods exhibit super-high fracture strength over 4000 MPa, high Young's modulus over 200 GPa, elastic strain of 0.02 and plastic strain up to 0.005. The bulk glassy alloys also exhibit good soft-magnetic properties, i.e., high saturation magnetization of 0.8–1.1 T, low coercive force below 3 A/m, and high permeability of 1.6–2.1 × 10⁴ at 1 kHz. The success of synthesizing a super-high strength Fe-based bulk glassy alloy with some compressive plastic strain and good soft-magnetic properties is encouraging for future development of Fe-based bulk glassy alloys as new engineering and functional materials.