Solderability of Electrodeposited Fe-Ni Alloys with Eutectic SnAgCu Solder

Solderabilities of electrodeposited Fe-Ni alloys with SnAgCu solder were examined by wetting balance measurements and compared to those of pure Ni and pure Fe platings. Excellent solderability was found on the Ni-52Fe plating as both the wetting force and kinetics approached or exceeded those on the pure Ni. However, upon further increase in Fe content to 75 at. pct, the solderability of the alloy was severely degraded even though it was still better than that of the pure Fe plating. X-ray photoelectron spectroscopy showed that such a strong dependence of solderability on Fe content is related to the much thinner, incomplete oxide coverage of Ni-rich plating surface.

Correlation between Thermal Expansion and Magnetic Characteristics of Fe-Ni Alloys in Fe_(1-x)Ni_x/Cu Superlattices

Thermal expansion behaviors of FeNi alloys were investigated by means of X-ray diffraction technique within a Fe1 -xNix/Cu superiattice structure. It was found that with a Ni concentration of x = 0.35, FeNi alloy layers showed the well-known Invar behavior, but for alloy layers with either lower or higher Ni concentrations, thermal expansion coefficients were larger. Based on results of magnetic measurements it is concluded that FeNi alloy layers with Ni concentrations lower than the Invar composition are in a superparamagnetic state which leads not only to low spontaneous magnetizations but also to large thermal expansions of the alloy layers.

Manufacture of μ-PIM gear mold by electroforming of Fe-Ni and Fe-Ni W alloys

The micro gear mold for powder injection molding was made by electroforming process of Fe-Ni and Fe-Ni-W alloys using UV-lithography process. Kinetics and activation energies in electroplating of both alloys were investigated to determine the best process conditions. Fe content within electrodeposited Fe-Ni alloys increased with the increase of rotating disk speed and the decrease of temperature and it is considered from the calculated activation energy of iron content that the rate determining step is controlled by mass transfer. Iron content in Fe-Ni electrodeposit varied from 58.33% to 70.45% by increasing current density from 2 to 6 A/drn2. Also, iron content in Fe-Ni-W electrodeposit increased from 59.32% to 70.15%, nickel content decreased from 27.86% to 17.07% and the content of tungsten was almost consistent in the range of 12.78%-12.82% although the current density increases from 1.5 to 5 A/dm^2. For the electroforming of micro gear mold, SU-8 mandrel with 550 μm in diameter and 400 μm in height was prepared by UV-lithography processing. Subsequently, Fe-36Ni and Fe-20Ni-13W alloys micro gear molds were electroformed successfully. Surface hardness values of the electroformed micro molds were measured to be HV490 and HV645, respectively.

超声波电沉积制备Fe-Ni-Co合金箔

Fe-Ni-Co合金箔是过渡金属合金的一种重要类型,在储氢和磁性材料领域具有巨大的应用前景。本研究在氨基磺酸盐-氯化物电镀液体系中,采用电沉积法在纯钛基底上制备出铁基Fe-Ni-Co合金箔,考察pH值、温度、电流密度、超声波功率对Fe-Ni-Co合金箔的形貌、化学成分、晶体结构的影响。结果表明,当pH=2.0、温度为60℃、电流密度为50 mA/cm^(2)、超声波功率为45 W时,合金箔表面平整且气孔较少,杂质元素含量低,截面成分分布较均匀;合金是以Ni为溶剂、Fe和Co为溶质的置换型固溶体,为面心立方的γ-(Fe, Ni)相,硬度及耐腐蚀性能均较好。

THERMODYNAMICS OF MARTENSITIC TRANSFORMATION IN Fe-Mn-C AND Fe-Ni-C ALLOYS

A Central Atom Model is introduced and the LFG and Hsu models are modified in order to evaluate the driving force for the martensitic transformation in Fe-Mn-C and Fe-Ni-C al- loys.The results show that the relationship between the driving force and the yield strength of austenite at Ms temperature,σ_(0.2)~γ/M_s,fits Hsu's formula;ΔG~=2.1σ_(0.2)~γ/M_s+907 J/mol.The M_s temperatures of Fe-Mn-C and Fe-Ni-C alloys are also calculated.The calculated results are in good agreement with experimental values.

Powder injection molding of Fe-Ni soft magnetic alloys

With miniaturization and complication of the shape of electronic devices in recent years,powder injection molding(PIM)seems to be a suitable process for fabricating the higher performance soft magnetic components.In this paper,high quality Fe-50Ni soft magnetic alloy was fabricated by PIM with carbonyl iron and nickel,and the effect of sintering process on its microstructure and magnetic properties were investigated.The mechanical and magnetic properties can be obviously improved by increasing the sintering temperature or using the hydrogen atmosphere instead of high vacuum,which causes by the increase of grain size and the densification.At the optimum sintering conditions,the PIM Fe-50Ni soft magnetic alloy with high properties are obtained,whose relative density,tensile strength,B_(m),H_(c),μ_(m)are 97%,465 MPa,1.52 T,16.62 A·m^(-1),42.5 mH·m^(-1),respectively.

负载型Fe-Ni纳米合金的制备及其催化丁二烯选择性加氢性能

采用尿素沉积-沉淀法制备了负载型Fe-Ni纳米合金催化剂,通过调变Fe/Ni摩尔比,研究了金属组分对其还原温度、合金结构及催化丁二烯选择性加氢性能的影响。结果表明:Fe-Ni复合能有效降低Fe、Ni单金属催化剂的还原温度;随着Fe摩尔分数由0增加至100%,金属相结构逐渐由面心立方向体心立方结构转变;在催化加氢过程中,Fe的引入降低了Ni基催化剂活性,但丁烯选择性得到大幅提高;当Fe/Ni摩尔比为25/75时,Fe_(25)Ni_(75)/TiO_(2)-R催化剂中富Ni的Ni3Fe相在丁二烯催化活性(完全转化温度T_(100%)约95℃)和单烯烃选择性(>93%)最佳。

时效处理对Fe-Ni基奥氏体合金耐点蚀性能的影响

针对Fe-Ni基奥氏体合金在740℃时效处理后的析出相随时效时间的演变进行探究;并通过电化学腐蚀试验以及Mott-Schottky分析,研究了时效处理对合金耐腐蚀性能的影响。结果表明:740℃时效处理可以促进γ′沉淀强化相[Ni_(3)(Al,Ti)]在合金中的析出;随时效时间的增加,γ′析出相的密度和尺寸增加;同时,时效处理会增加合金表面点缺陷数量,降低合金钝化膜致密性,从而导致合金耐点蚀性降低;通过恒电位阳极极化处理能够有效降低合金表面点缺陷数量,提高合金耐点蚀性。

Accelerated design of high-performance Mg-Mn-based magnesium alloys based on novel bayesian optimization

Magnesium(Mg),being the lightest structural metal,holds immense potential for widespread applications in various fields.The development of high-performance and cost-effective Mg alloys is crucial to further advancing their commercial utilization.With the rapid advancement of machine learning(ML)technology in recent years,the“data-driven''approach for alloy design has provided new perspectives and opportunities for enhancing the performance of Mg alloys.This paper introduces a novel regression-based Bayesian optimization active learning model(RBOALM)for the development of high-performance Mg-Mn-based wrought alloys.RBOALM employs active learning to automatically explore optimal alloy compositions and process parameters within predefined ranges,facilitating the discovery of superior alloy combinations.This model further integrates pre-established regression models as surrogate functions in Bayesian optimization,significantly enhancing the precision of the design process.Leveraging RBOALM,several new high-performance alloys have been successfully designed and prepared.Notably,after mechanical property testing of the designed alloys,the Mg-2.1Zn-2.0Mn-0.5Sn-0.1Ca alloy demonstrates exceptional mechanical properties,including an ultimate tensile strength of 406 MPa,a yield strength of 287 MPa,and a 23%fracture elongation.Furthermore,the Mg-2.7Mn-0.5Al-0.1Ca alloy exhibits an ultimate tensile strength of 211 MPa,coupled with a remarkable 41%fracture elongation.

Relationship between the unique microstructures and behaviors of high-entropy alloys

High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness.By contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as structure.In accordance with Shannon entropy,structure is analogous to information.Generally,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its properties.In addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural designs.The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous examples.These features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion resistance.In this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.

Research advances of magnesium and magnesium alloys globally in 2023

Magnesium materials have attracted the attention of many researchers,and the related research is expanding.This article summarizes the advance in the research and development of magnesium materials globally in 2023 from bibliometric and scientific perspectives.More than 4680 articles on Mg and its alloys were published and indexed in the Web of Science(WoS)Core Collection database last year.The bibliometric analyses show that the traditional structural Mg alloys,functional Mg materials,and corrosion and protection of Mg alloys are still the main research focus.Therefore,this review paper mainly focuses on the research progress of Mg cast alloys,Mg wrought alloys,bio-magnesium alloys,Mg-based energy storage materials,corrosion and protection of Mg alloys in 2023.In addition,future research directions are proposed based on the challenges and obstacles identified throughout this review.

Influence of Metalloid Elements on the Magnetic Properties and Anisotropy of FeNi-based Amorphous Alloys

The magnetic properties and anisotropy of amor- phous(Fe_(80)Ni_(20))_(78)Si_xB_(22-x).alloys have been investigated systematically.The maximum permeability,coercive force and remanence have been determined for as-prepared and annealed samples,The results on the technical magnetic properties of this alloy system have been discussed and compared with Masumoto's.

Microstructure and mechanical properties stability of pre-hardening treatment in Al-Cu alloys for pre-hardening forming process

The stability of the microstructure and mechanical properties of the pre-hardened sheets during the pre-hardening forming(PHF)process directly determines the quality of the formed components.The microstructure stability of the pre-hardened sheets was in-vestigated by differential scanning calorimetry(DSC),transmission electron microscopy(TEM),and small angle X-ray scattering(SAXS),while the mechanical properties and formability were analyzed through uniaxial tensile tests and formability tests.The results in-dicate that the mechanical properties of the pre-hardened alloys exhibited negligible changes after experiencing 1-month natural aging(NA).The deviations of ultimate tensile strength(UTS),yield strength(YS),and sheet formability(Erichsen value)are all less than 2%.Also,after different NA time(from 48 h to 1 month)is applied to alloys before pre-hardening treatment,the pre-hardened alloys possess stable microstructure and mechanical properties as well.Interestingly,with the extension of NA time before pre-hardening treatment from 48 h to 1 month,the contribution of NA to the pre-hardening treatment is limited.Only a yield strength increment of 20 MPa is achieved,with no loss in elongation.The limited enhancement is mainly attributed to the fact that only a limited number of clusters are transformed into Guinier-Preston(GP)zones at the early stage of pre-hardening treatment,and the formation ofθ''phase inhibits the nucleation and growth of GP zones as the precipitated phase evolves.

HIGH TEMPERATURE OXIDATION AND STRUCTURE OF SCALE AND WHISKERS FOR Fe-Ni-Cr SEALING ALLOYS

The oxidation rate,the growth,morphology and structure of oxide scale and whiskers for Fe-Ni-Cr sealing alloys in H_2-H_2O atmosphere at high temperatures have been studied. The growth rate of scale is controlled by diffusion.The scale is composed of Cr_2O_3 and spinel(Fe,Mn)O·Cr_2O_3 and the oxide whisker,are spinel(Fe,Mn)O·Cr_2O_3.

Disaccommodation in Fe-Ni Based Amorphous Alloys

The disaccommodation of magnetic per- meability,specific magnetization and linear magnetostriction of amorphous(Fe_xNi_(1-x))_(76)- Si_8B_(16)alloys were measured.It was found that the disaccommodation obtained at lower temperature is a monotonically decreasing function of Fe content, however,a peak is observed at higher temperature. The experimental results are discussed on the basis of magnetostrictive interaction and atomic directional ordering.

Microstructure and damping properties of LPSO phase dominant Mg-Ni-Y and Mg-Zn-Ni-Y alloys

This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.

Recent innovations in laser additive manufacturing of titanium alloys

Titanium(Ti)alloys are widely used in high-tech fields like aerospace and biomedical engineering.Laser additive manufacturing(LAM),as an innovative technology,is the key driver for the development of Ti alloys.Despite the significant advancements in LAM of Ti alloys,there remain challenges that need further research and development efforts.To recap the potential of LAM high-performance Ti alloy,this article systematically reviews LAM Ti alloys with up-to-date information on process,materials,and properties.Several feasible solutions to advance LAM Ti alloys are reviewed,including intelligent process parameters optimization,LAM process innovation with auxiliary fields and novel Ti alloys customization for LAM.The auxiliary energy fields(e.g.thermal,acoustic,mechanical deformation and magnetic fields)can affect the melt pool dynamics and solidification behaviour during LAM of Ti alloys,altering microstructures and mechanical performances.Different kinds of novel Ti alloys customized for LAM,like peritecticα-Ti,eutectoid(α+β)-Ti,hybrid(α+β)-Ti,isomorphousβ-Ti and eutecticβ-Ti alloys are reviewed in detail.Furthermore,machine learning in accelerating the LAM process optimization and new materials development is also outlooked.This review summarizes the material properties and performance envelops and benchmarks the research achievements in LAM of Ti alloys.In addition,the perspectives and further trends in LAM of Ti alloys are also highlighted.

INFLUENCE OF DISPERSIVELY PRECIPITATED PARTICLES ON MARTENSITE MORPHOLOGY IN Fe-Ni-Co-Ti ALLOYS

The Martensite formed at low temperatures in Fe-Ni-Co-Ti alloys is featured as thin plate when the size of γ' dispersively precipitated particles was about 20—50 nm.The interface of martensite plate is not smooth.If the γ'particles are sized less than 5 nm,the thin plate martensite with thermoelastisity may be found at low temperatures,whi greater than 5 nm, intermittent martensite may occur,and the plate martensite increases both in size and quantity with the coarsening of the γ particles.The lenticular or butterfly martensite forms at low tem- peratures until the γ' particles are up to 10—5 nm.

Prediction of the thermal conductivity of Mg–Al–La alloys by CALPHAD method

Mg-Al alloys have excellent strength and ductility but relatively low thermal conductivity due to Al addition.The accurate prediction of thermal conductivity is a prerequisite for designing Mg-Al alloys with high thermal conductivity.Thus,databases for predicting temperature-and composition-dependent thermal conductivities must be established.In this study,Mg-Al-La alloys with different contents of Al2La,Al3La,and Al11La3phases and solid solubility of Al in the α-Mg phase were designed.The influence of the second phase(s) and Al solid solubility on thermal conductivity was investigated.Experimental results revealed a second phase transformation from Al_(2)La to Al_(3)La and further to Al_(11)La_(3)with the increasing Al content at a constant La amount.The degree of the negative effect of the second phase(s) on thermal diffusivity followed the sequence of Al2La>Al3La>Al_(11)La_(3).Compared with the second phase,an increase in the solid solubility of Al in α-Mg remarkably reduced the thermal conductivity.On the basis of the experimental data,a database of the reciprocal thermal diffusivity of the Mg-Al-La system was established by calculation of the phase diagram (CALPHAD)method.With a standard error of±1.2 W/(m·K),the predicted results were in good agreement with the experimental data.The established database can be used to design Mg-Al alloys with high thermal conductivity and provide valuable guidance for expanding their application prospects.

Microstructures,corrosion behavior and mechanical properties of as-cast Mg-6Zn-2X(Fe/Cu/Ni)alloys for plugging tool applications

Mg-6Zn-2X(Fe/Cu/Ni)alloys were prepared through semi-continuous casting,with the aim of identifying a degradable magnesium(Mg)alloy suitable for use in fracturing balls.A comparative analysis was conducted to assess the impacts of adding Cu and Ni,which result in finer grains and the formation of galvanic corrosion sites.Scanner electronic microscopy examination revealed that precipitated phases concentrated at grain boundaries,forming a semi-continuous network structure that facilitated corrosion penetration in Mg-6Zn-2Cu and Mg-6Zn-2Ni alloys.Pitting corrosion was observed in Mg-6Zn-2Fe,while galvanic corrosion was identified as the primary mechanism in Mg-6Zn-2Cu and Mg-6Zn-2Ni alloys.Among the tests,the Mg-6Zn-2Ni alloy exhibited the highest corrosion rate(approximately 932.9 mm/a)due to its significant potential difference.Mechanical testing showed that Mg-6Zn-2Ni alloy possessed suitable ultimate compressive strength,making it a potential candidate material for degradable fracturing balls,effectively addressing the challenges of balancing strength and degradation rate in fracturing applications.