Microstructure and mechanical properties of AZ61 magnesium alloy parts achieved by thixo-extruding semisolid billets prepared by new SIMA

New strain induced melt activation（new SIMA） method was employed to prepare high-quality semisolid billet of AZ61 magnesium alloy.Optical microscopy and tensile test were used to study the microstructure and mechanical properties of the thixo-extruded component.The results showed that the optimal process parameters for achieving the complete filling status involved the applied pressure of 784 MPa,the pressure holding time of 90 s and the die temperature of 450 ℃.Compared to semisolid isothermal treatment,high mechanical properties such as the tensile strength of 300.5 MPa and elongation of 22% and fine microstructure were obtained in the thixo-extruded parts.With increasing the isothermal temperature and holding time,the tensile strength and elongation were increased firstly and then decreased.When the press pass was increased from 1 to 4,the tensile strength and elongation of the thixo-extruded parts were greatly enhanced and microstructure was refined obviously.

Yixunite and Damiaoite—A Twin of New Native Alloys of Indium and Platinum from the Yanshan Mountains

Yixunite and damiaoite Were found in a cobalt- and copper-bearing platinum ore vein of a contact metasomatic deposit. The chief ore minerals are bornite, chalcopyrite, magnetite and carrollite. The platinum minerals include moncheite, sperrylite, daomanite, cobalt malanite and cooperite. Yixunite and damiaoite occur as immiscible globules, 1.0 to 2.0 mm in diameter. Yixunite is always in the central part of a globule. It is opaque with metallic lustre, bright white colour and black streak. HM = 5.8; VHN50 = 634 kg/mm2 (573-681 kg/ mm2); insoluble in HCl, HNO3, HF or H3PO4; no cleavage; no magnetism. Density is hard to measure because of small grain size. Calculated density = 18.21 g/cm3. Reflective colour is bright white with a yellowish tint. Isotropic. The mean analytical results (ranges) (%) are: Pt 82.8 (81.8-83.6), In 16.4(15.6-17.1) and total 99.2. The empirical formula (based on 4 atoms) is Pt2.993 In1.007 . The five strongest lines of X-ray diffraction (hkl, d,I) are 111, 2.30 (100); 200, 1.99 (60); 202, 1.411 (40);311, 1.203 (80); 222, 1.151(40). Space group: Pm3m with a =0.3988(3) nm and Z= 1. Damiaoite occurs as single globules or was exsolved from yixunite. Opaque with metallic lustre; bright white colour with black streak; HM = 5.3; VHN50 = 485 kg/mm2 (434-529 kg/mm2); insoluble in HC1, HNO3, HF or H3PO4; cleavage: no; magnetism: no. Density: hard to measure because of small grain size. Calculated density = 10.95 g/ cm3. Reflective colour is bright white with a yellowish tint. Isotropic. The mean analytical results (ranges) (%) are Pt 45.6 (45.4-46.0), In 53.5 (52.4-53.9), total 99.1. The empirical formula (based on 3 atoms) is Pt0.002 In1.998. The six strongest lines of X-ray diffraction (hkl.d,I) are 220,2.25 (100); 311,1.92 (60); 400,1.59 (60); 422,1.299 (80); 440,1.125 (60); 620,1.006 (70). Space group: Fm3m with a = 0.6364 (3) nm and Z = 4.

Semi-solid A356 alloy slurry for rheocasting prepared by a new process

To obtain the semi-solid slurry with uniform and fine structure morphology that satisfies the requirement of rheocasting process, a new process for preparing semi-solid AI alloy slurry was developed, in which local chilling was combined with low superheat pouring and slight electromagnetic stirring （LSPSEMS）. The morphology and the size of primary a-AI in the A356 alloy slurry prepared with the new process, i.e., LSPSEMS with local chilling, were investigated using MIAPS image analyzing software, and the grain refinement mechanism was discussed. The results indicate that the semi-solid primary phase consists of particle-like or globular-like a-AI, and the morphology and grain size of primary a-AI in the slurry can be markedly improved by the new process. The fine primary a-AI distributes uniformly in the slurry, which satisfies the requirement of rheocasting. Compared with the alloy prepared by LSPSEMS, the average equal-area-circle grain diameter of primary a-AI in semi-solid A356 alloy ingot prepared by the new process is decreased from 85.6μm to 68.8 μm at the central area, 112.6 μm to 77.6 μm at the transition area and is 84.7 μm in the edge area, respectively. The corresponding shape factor of primary a-AI is increased from 0.78 to 0.83, 0.54 to 0.77 and 0.28 to 0.59, respectively. In addition, the pouring temperature could be suitably raised from 620-630℃ of the traditional process to 650℃ using this technique, which is convenient for practical operation. The mechanism of grain refinement, in the new process, is that the local chilling quickens up the temperature decrease in the center of the melt. The nuclei could not grow up in a short time so the finer grains are formed in the melt.

Erratum to: New high-strength Ti–Al–V–Mo alloy: from high-throughput composition design to mechanical properties

Erratum to:International Journal of Minerals, Metallurgy and Materials Volume 26, Number 9, September 2019, Page 1151https://doi.org/10.1007/s12613-019-1854-1The original version of this article unfortunately contained a mistake. The presentation of Fig. 11 was incorrect. The correct version is given below:

A New Sound Alloy for High Grade Wind Instruments

A new sound alloy, abbreviated to S, has been developed by the General Research Institutefor Non-ferrous Metals, Beijing. The alloy is very suitable for making trumpets, trombones, tenorhorns, saxaphones and other kinds of wind instruments. Beijing Wind Instrument Factory, which is the largest one in China, has used Salloy formanufacturing 5200 type trompets, the sound performance of which has been examined with fre-quency analysis and experimented by famous musical experts. The results show that the 5200 typetrumpets made of Salloy have excellent quality, accurate intonation and ease of response at

A Study of Making Iron Aluminide Alloy Powders with New Rotating Electrode Technology

A new process was used for producing FeAl alloy pow de rs with double consumable rotating electrodes and the powders made in this appar atus were analyzed. In this new technology, tungsten rod serves as a cathode ele ctrode, while the alloy rod as an anode electrode. The conventional rotating ele ctrode process must have an anode with pre-melting alloys; however, in this new process, using pure iron as cathode electrode and pure aluminum as anode electr ode can eliminate the step of pre-melting. The effects of process variables, which include electrode rotational speed, a nd electrode diameter of the mean particle diameter were determined. Results showed that both the rotational speed and diameter of electrodes would a ffect the mean diameter of particles. There are three kinds of powders with diff erent composition produced in this study and the possible mechanisms are discuss ed. The process parameters and volume mean diameter of the powders have been cor related to find an experimental equation. The results show that when the rotational speed and the diameter of the anode el ectrode are increased, the powders size will decrease. However, the powders size will increase with cathode electrode.

新型Al-Li-Cu-Mg合金蒙皮拉伸成形特性试验研究

随着新型Al-Li-Cu-Mg合金蒙皮在航空航天等高技术工业的应用日益广泛,新型Al-Li-Cu-Mg合金蒙皮拉伸成形特性已成为新型Al-Li-Cu-Mg合金板蒙皮成形质量精确控制以及蒙皮设计迫切需要解决的关键问题。因此,首先获得了新型T8态Al-Li-Cu-Mg合金的最佳热处理工艺参数;其次,采用试验方法,研究了不同热处理状态的拉伸成形过程,揭示了新型Al-Li-Cu-Mg合金板材的拉伸成形特性。发现通过固溶处理,后续时效能够显著提高新型T8态Al-Li-Cu-Mg合金材的拉形能力;在新型Al-Li-Cu-Mg合金板材拉形过程,桔皮现象主要出现在补拉阶段,蒙皮悬空区应变值>0.0215时,板材表面将出现桔皮,且与材料热处理状态无关。

Effect of duplex aging on microstructure and mechanical properties of near-βtitanium alloy processed by isothermal multidirectional forging

The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)alloy were investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that the finer secondaryαphase precipitates in the alloy after DA than SA(e.g.,149 nm for SA and 69 nm for DA,both after ST at 720℃).The main reason is that the pre-aging step(300℃)in the DA process leads to the formation of intermediateωphase nanoparticles,which assist in the nucleation of the acicular secondaryαphase precipitates.In addition,the strength of the alloy after DA is higher than that of SA at the specific ST temperature.A good combination is achieved in the alloy subjected to ST at 750℃,followed by DA(UTS:1450 MPa,EL:3.87%),which is due to the precipitation of nanoscale secondaryαphase by DA.In conclusion,DA is a feasible process for this new near-βtitanium alloy.

Anodic Layer of Pb-Ca-Sn-Ce Alloy for Maintenance-Free Lead/Acid Batteries

The anodic films of novel Pb-Ca-Sn-Ce alloy, traditional Pb-Ca-Sn and Pb-Sb alloys formed in sulfuric solution at anodic +0.9 V potential corrosion for 6 h were investigated by means of XPS, XRD methods and AC impedance measurement. The results show that the growth of Pb(Ⅱ) oxide on the new Pb-Ca-Sn-Ce alloy surface is inhibited. The AC impedance measurement shows that resistance of the corrosion layer of novel Pb-Ca-Sn-Ce alloy decreases. It is found that the novel Pb-Ca-Sn-Ce alloy can encourage the development of PbO2 in the scale, and enhance the conductivity of the anodic scale. Hence the deep recycling properties of the battery can be expected better.

Applying Study of Hydrogen Storage Alloy

Hydrogen is an important source of energy.The natural resouces of hydrogen is plenty and it gives us lots of heat, and it is dean. One of difficulties of developing hydrogen sources of energy is hydrogen storage. Hydrogen storage tank is either dangous or a little of capacity. Liquid hydrogen occupys small space. Liquefaction temperature of hydrogen is -253℃ and need better heat insulation protection, the volumn and weight of heat insulation layer are equal to hydrogen storage tank. Hydrogen storage utillizing hydrogen storage material is a very safety, economical and effective method. Hydrogen storage material is either a medium of sofid hydrogen storage or is negative pole active material of Ni-H battery,and is the one of key technoloy of fuel and Ni-H battery, it is an important material of new sources of energy too.Nanotechnology is introduced Mg-matrix hydrogen storage alloy and is achieved progress gteatly,but hydrogen storage alloy need be mode further improvment on applying investigation.

基于有限元仿真的钛合金喷丸技术应用综述

喷丸强化工艺作为一种常用的表面强化技术,在钛合金相关零部件的表面强化中起到重要作用,有限元技术在探究喷丸强化工艺机理和强化效果中应用广泛。目前,多数喷丸仿真研究都是以钢和铝合金为材料,以钛合金为材料的喷丸仿真研究相对较少。本文总结了国内外学者关于钛合金传统喷丸仿真技术、钛合金新型喷丸仿真技术以及钛合金传统喷丸技术与新型喷丸仿真技术的联系,并对钛合金喷丸仿真方面的发展趋势进行展望。

β相区固溶处理对新型TB17钛合金晶粒尺寸及均匀性的影响

首先对新型TB17钛合金进行了β相区(900~1050℃)保温不同时间(30~120 min)的固溶处理,并对固溶处理后合金晶粒尺寸进行了统计分析,研究了合金在β相区的晶粒生长行为及均匀性,计算了合金β相生长指数n和生长激活能Q,并建立了β相变点以上的β晶粒生长模型。结果表明,随保温时间的延长,合金β相的晶粒尺寸的变化趋势为先快速增加,后增加速率趋于缓慢。在较低加热温度(900~950℃)下,β晶粒缓慢增长,超过1000℃后,β晶粒快速增长。合金β相区晶粒平均生长指数为0.248,β相区晶粒生长激活能为51.9 kJ/mol;在晶粒尺寸均匀性方面,随保温时间的增加,β晶粒尺寸均匀性增加。保温时间低于60 min时,β晶粒尺寸均匀性差。β晶粒尺寸与保温时间存在幂函数关系。建立了β相变点以上的β晶粒生长模型Dn-D0=13494×t 0.248 exp(-71903/RT),模型计算值与实验数据的平均误差为5.5%。

碳中和目标下新一代超高参数煤电机组技术体系

该文围绕“双碳”目标,分析煤电对支撑我国新型电力系统的重要作用以及燃煤发电技术的主要发展方向,提出下一代超超临界燃煤发电技术体系,并简要介绍相关研发实践。该技术体系基于国产化的HT700系列高温合金材料,耦合高参数煤电、煤电灵活性、烟气污染物低温氧化吸附(cold oxidation adsorption process,COAP与COAP+)脱除近零排放技术、碳补集、利用与封存技术(carboncapture,utilization and storage,CCUS)、数字化智能化及燃煤耦合多源固废发电等前沿技术,建议开发新一代超高参数燃煤发电机组,实现机组煤耗与能耗水平、运行稳定性、灵活性的有机统一,支撑我国“双碳”目标的实现。

新型钛合金焊接结构疲劳裂纹扩展速率试验研究

为了研究尺度效应及热处理工艺对新型钛合金材料疲劳性能的影响,本文对新型钛合金母材及焊接结构在不同尺度效应和热处理工艺下的力学性能和疲劳性能开展试验,分析尺度效应和热处理工艺对新型钛合金材料疲劳性能的影响规律。研究结果表明,仅经过低温热处理的新型钛合金焊接结构疲劳寿命要超过经过高温-低温热处理后的焊接接头近1.53倍;尺度效应对焊接结构的力学性能影响较大,对母材影响较小;随着尺度增大新型钛合金的裂纹扩展寿命增大,但裂纹扩展速率并无明显变化。

汽车轻量化技术研究

当今,随着石油资源的日益减少以及人们环保意识的不断增强,新能源汽车的发展日益蓬勃,其取代传统燃油车的时间指日可待。然而,制约新能源汽车发展的因素有很多,其中整车重量是影响新能源汽车续航里程的重要因素,因此,车身轻量化技术的发展迫在眉睫。本文阐述了汽车轻量化的开发路径、铝在汽车轻量化中的应用。

不同参数下新型灌浆套筒力学性能研究

为研究环肋数量、环肋间距、环肋深度、钢筋锚固长度、钢筋直径对以无缝钢管制成的新型灌浆套筒力学性能的影响,以Q390B低合金无缝钢管为原材料,设计制作23组共69个全灌浆套筒连接试件进行单向拉伸试验。此外,采用ABAQUS进行数值模拟,并将数值分析结果与试验值进行对比,分析上述参数对套筒试件承载力、破坏模式、应力分布等的影响。结果表明:数值分析结果与试验值吻合良好,充分验证了数值模型分析的可行性;套筒环肋不宜设置在钢筋弹性段区域及套筒中部位置附近;环肋数量在一定区间内增加有利于提高套筒承载力;环肋间距与环肋深度过大、过小均不利于提高套筒承载力,且应力集中现象明显;锚固长度不小于6倍钢筋直径即可满足套筒承载力要求,且套筒内径与钢筋直径差值不宜小于12mm。

新能源汽车用铸造铝合金的研究现状和发展趋势

新能源汽车工业的迅猛发展,对铸造铝合金的低比重、高强度、高韧性提出了更高需求。为确保足够的力学性能,汽车铝合金零部件通常采用可热处理的铸造铝合金,同时,为节省整车制造成本,先进的一体化压铸技术和免热处理铸造铝合金已成为重点发展的新方向。本文介绍近10年来国内外不同体系铸造铝合金的研究现状,包括铸造铝合金的主要种类、成分设计、铸造工艺和组织调控等方面的新进展和新探索。

铝合金电缆在充电桩领域内应用的可行性研究

铝合金电缆作为一种新型电缆,具有重量轻、导电优良、价格低廉等特点,但相较于铜芯电缆而言,铝合金电缆的稳定性能、机械性能以及电气性能均不及铜芯电缆。通过对比铝合金电缆与传统铜芯电缆的机械性能、热稳定性能、电气性能和性价比等相关特性,结合新能源充电站和分布式光伏电站的实际情况来论证铝合金电缆在新能源充电站和分布式光伏项目上替代铜芯电缆的可行性。