Fe含量对粉末冶金Cu-Fe合金显微组织与性能的影响

研究Fe含量对粉末冶金Cu-Fe合金显微组织及性能的影响。采用电火花等离子烧结、冷轧以及时效处理工艺制备4种不同铁含量(5%、10%、20%和40%,质量分数)的Cu-Fe合金。研究结果表明,随着Fe含量从5%(质量分数)增加到40%(质量分数),Fe相由离散球形分布演变为连续交错分布,Fe相尺寸从0.29μm增加到1.20μm;时效态的Cu-Fe合金的屈服强度从411.5 MPa提高到788.8 MPa,电导率从62.5%(IACS)降低到42.0%(IACS)。在以上结果的基础上,提出一种混合法则计算Cu基体、初级Fe相和次级Fe相对屈服强度的贡献,可较好地预测Fe含量高于10%(质量分数)合金的力学性能。

高性能Cu-Fe合金薄带材及其短流程制备技术

为了解决Cu-Fe合金常规制备流程中重力分层的问题,利用铸轧工艺的亚快速凝固特点抑制其液相分离,并结合Marangoni效应及热泳力的耦合作用合理调控铸轧参数,获得厚度为2.2~2.4 mm、铁磁相尺寸和分布可控的Cu-20%Fe和Cu-30%Fe带材。通过金相与EBSD分析确定铸带形成了Cu相-富Fe相-Cu相的“三明治”层状复合结构,其中Cu-20%Fe铸带中的Fe相分布更为均匀,且EBSD分析结果表明凝固层中形成了大量的低能晶界,如Σ1和Σ3等。将Cu-20%Fe合金从2.4 mm冷轧至0.4 mm,在不同温度下进行热处理后继续冷轧至0.12 mm。结果表明:450℃热处理对轧板性能更好,导电率超过50%IACS,抗拉强度超过600 MPa,均匀伸长率达到7.5%,饱和磁化强度超过4.24×10^(5)A/m。

人工时效处理对体育器材焊接用Al-6Si-2Cu-Fe合金组织与性能的影响

Al-Si-Cu铝合金广泛应用于体育器材中取代铁制零件,该合金的力学特性是其应用中重要的参考依据,其中Al-6Si-2Cu-Fe作为代表合金之一,不同的热处理状态会显著影响合金的显微组织与力学性能,为此,文中研究了不同人工时效处理方式对Al-6Si-2Cu-Fe合金的影响。按先后顺序对合金进行了3种不同的时效处理,分别是预时效、单级时效和双级时效。通过硬度测试、拉伸测试、冲击试验、金相观察和扫描电子显微镜能谱分析进行表征。结果表明,由于时效处理的不同,相组成和形态微结构存在差异,每种处理的差异可以在析出相的显微组织形态中观察到,各析出相包括弥散的、圆形和针状等形态,这些相结构显著影响了合金的力学性能。测试结果显示,单级时效处理获得了最高的硬度和抗拉强度,其分别为160.16 HB和201.45 MPa;预时效处理的冲击韧性最高,其吸收能量为18.55 J。

退火温度对Cu-Fe-P合金显微组织及性能的影响

对C19210(Cu-0.1Fe-0.03P)合金经不同温度退火后的显微组织进行观察,并对其抗拉强度、显微硬度、导电率等进行测试。结果表明,在200~500℃退火时,轧制态C19210合金依次发生的是回复和再结晶。当退火温度升高时,C19210合金的抗拉强度呈下降趋势,但在加工硬化减弱、弥散强化加强及晶粒尺寸演变的共同作用下,450℃时抗拉强度轻微上升至416 MPa。C19210合金的延伸率和电导率随退火温度的升高呈上升趋势,显微硬度呈下降趋势,但由于第二相析出,400℃退火时硬度提升至128HV,随后迅速下降。

Fe元素含量和形变工艺对Cu-Fe合金组织与性能影响的研究进展

高强高导铜合金在电子、机械、交通通信等领域应用广泛,而Cu‐Fe合金因其较好的强度和导电性,低廉的成本成为了高强高导铜合金的重要研究方向之一。综述了高强高导Cu‐Fe合金的研究进展,针对Cu‐Fe合金强度和导电性倒置问题,总结了Fe元素含量对合金组织、抗拉强度和导电性的影响规律;阐述了拉拔、轧制等形变工艺对合金组织与性能的影响及其机理;展望了高强高导Cu‐Fe合金的未来发展趋势;提出第三元素(如P,Ag,Co,Ni或稀土)的合金化调控是有效改善Cu‐Fe合金综合性能的发展方向之一。

激光熔化沉积Cu-Fe合金的液相分离组织及力学性能研究

难混溶合金由于亚稳难混溶间隙的存在,在制备过程中极易产生偏析甚至分层现象,严重影响材料的使用性能。激光熔化沉积小熔池无宏观偏析的特点,为制备均质难混溶合金提供了潜在途径。本文选取典型难混溶Cu-Fe合金作为研究对象,采用激光熔化沉积制备了薄壁状Cu_(35)Fe_(65)难混溶合金,研究了合金的物相组成、微观组织形貌与力学性能。结果表明:合金由体心立方(bcc)结构的α-Fe相与面心立方(fcc)结构的Cu相组成;合金呈现典型的液相分离形貌,由网络状Cu相与块状α-Fe相构成,α-Fe相平均直径为8μm;合金屈服强度为397 MPa,抗拉强度为484 MPa,延伸率为16.5%,断裂方式主要为韧性断裂;合金的导电率为19%IACS,较高的α-Fe相体积分数可能是影响合金电阻率的主要因素。本研究表明,激光熔化沉积技术有望成为高性能难混溶合金的有效制备方式。

超声法制备负载Cu-Fe分子筛催化剂及其催化氧化甲苯性能研究

挥发性有机化合物(VOCs)是大气污染物的重要组成部分,可对生态环境和人体健康造成严重危害,因此设计并制备高效催化剂降解VOCs尤为重要。作为商业应用的催化剂,分子筛具有稳定性好和抗毒能力强等优点,然而单一分子筛催化活性较差,需要负载活性组分进一步提高催化性能。采用超声法,分别以ZSM-5、Beta和SAPO-34分子筛作载体同时负载Cu、Fe过渡金属氧化物制备了Cu-Fe/ZSM-5、Cu-Fe/Beta和Cu-Fe/SAPO-34催化剂并用于甲苯催化氧化。催化活性测试结果表明,Cu-Fe/ZSM-5催化剂表现出最佳催化活性,300℃下甲苯转化率可达90%。X-射线衍射(XRD)分析结果表明,同时负载Cu、Fe金属氧化物未对分子筛结构造成明显破坏,且金属氧化物具有良好的分散性。NH_(3)程序升温(NH_(3)-TPD)分析结果表明,酸性不是影响催化活性的唯一因素。原位漫反射红外(in situ DRIFT)和色谱质谱联用(GC-MS)分析结果表明,催化活性较好的催化剂上生成的中间产物较少,而催化活性较差的催化剂上会生成更多的中间产物。

Cu-Fe合金的制备及性能研究现状

Cu-Fe合金由于其优良的导电性和较高的硬度及强度等物理性能,被广泛应用于高强高导合金领域。本文综述了Cu-Fe合金的制备方法,分析对比了各种Cu基合金制备方法的优劣性,并在此基础上概括了强化手段对不同方法所制得合金相关性能的影响,指出了微观组织与合金电学及力学性能之间的相互作用,最终提出了快速凝固制备Cu-Fe合金将是未来的主要发展方向,并具有较好的发展前景。

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.

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.

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.

Effect of icosahedral phase formation on the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li(in wt.%)based alloys

Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC process.With regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li interfaces.Moreover,the SCC of the two alloys was concerned with hydrogen embrittlement(HE)mechanism.

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 and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review

High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.

Transformation of long-period stacking ordered structures in Mg-Gd-Y-Zn alloys upon synergistic characterization of first-principles calculation and experiment and its effects on mechanical properties

Based on experiments and first-principles calculations,the microstructures and mechanical properties of as-cast and solution treated Mg-10Gd-4Y-xZn-0.6Zr(x=0,1,2,wt.%)alloys are investigated.The transformation process of long-period stacking ordered(LPSO)structure during solidification and heat treatment and its effect on the mechanical properties of experimental alloys are discussed.Results reveal that the stacking faults and 18R LPSO phases appear in the as-cast Mg-10Gd-4Y-1Zn-0.6Zr and Mg-10Gd-4Y-2Zn-0.6Zr alloys,respectively.After solution treatment,the stacking faults and 18R LPSO phase transform into 14H LPSO phase.The Enthalpies of formation and reaction energy of 14H and 18R LPSO are calculated based on first-principles.Results show that the alloying ability of 18R is stronger than that of 14H.The reaction energies show that the 14H LPSO phase is more stable than the 18R LPSO.The elastic properties of the 14H and 18R LPSO phases are also evaluated by first-principles calculations,and the results are in good agreement with the experimental results.The precipitation of LPSO phase improves the tensile strength,yield strength and elongation of the alloy.After solution treatment,the Mg-10Gd-4Y-2Zn-0.6Zr alloy has the best mechanical properties,and its ultimate tensile strength and yield strength are 278.7 MPa and 196.4 MPa,respectively.The elongation of Mg-10Gd-4Y-2Zn-0.6Zr reaches 15.1,which is higher than that of Mg-10Gd-4Y0.6Zr alloy.The improving mechanism of elastic modulus by the LPSO phases and the influence on the alloy mechanical properties are also analyzed.

Review on synergistic damage effect of irradiation and corrosion on reactor structural alloys

The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors.The competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this paper.Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.

Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

Treatment of Phenol Wastewater with Cu-Fe/AC Catalyst by Continuous CWPO

The Cu-Fe/AC catalyst was prepared by microwave-assisted synthesis, and its morphological characteristics were characterized. The degradation effect of phenol wastewater by catalytic wet peroxide oxidation(CWPO) was studied, and the response surface methodology(RSM) was used to analyze the influencing factors of the removal rate of COD. The experimental results showed that under the conditions of reaction temperature 80 ℃, reaction time 90 min, initial pH 3.1 and H_(2)O_(2)addition 2.2 g/L, the removal rate of COD reached 82%. The results of response surface methodology indicated that under the conditions of reaction temperature 100 ℃, reaction time 64 min, initial pH 3.3 and H_(2)O_(2)addition 2.7 g/L, the removal rate of COD was up to 86%. After Cu-Fe/AC catalyst was reused for 4 times, the removal rate of COD was still above 80%, revealing that the catalyst showed good catalytic performance.

New insights on the high-corrosion resistance of UHP Mg-Ge alloys tested in a simulated physiological environment

UHP Mg-Ge alloys was recently found to provide excellent corrosion resistance.This paper provides new insights on the mechanism of improved corrosion resistance of UHP Mg-Ge alloys in Hanks’solution.The studied UHP Mg-0.5Ge and UHP Mg-1Ge alloys showed superior corrosion resistance compared to UHP Mg and WE43,with the Mg-1Ge exhibiting the best corrosion performance.The exceptional corrosion resistance of the UHP alloy is attributed to(i)Mg_(2)Ge’s ability to suppress cathodic kinetics,(ii)Ge’s capability to accelerate the formation of a highly passive layer,and the(iii)low amounts of corrosion-accelerating impurities.

Microstructure and thermal properties of dissimilar M300–CuCr1Zr alloys by multi-material laser-based powder bed fusion

Multi-material laser-based powder bed fusion (PBF-LB) allows manufacturing of parts with 3-dimensional gradient and additional functionality in a single step. This research focuses on the combination of thermally-conductive CuCr1Zr with hard M300 tool steel.Two interface configurations of M300 on CuCr1Zr and CuCr1Zr on M300 were investigated. Ultra-fine grains form at the interface due to the low mutual solubility of Cu and steel. The material mixing zone size is dependent on the configurations and tunable in the range of0.1–0.3 mm by introducing a separate set of parameters for the interface layers. Microcracks and pores mainly occur in the transition zone.Regardless of these defects, the thermal diffusivity of bimetallic parts with 50vol% of CuCr1Zr significantly increases by 70%–150%compared to pure M300. The thermal diffusivity of CuCr1Zr and the hardness of M300 steel can be enhanced simultaneously by applying the aging heat treatment.