C15

C15是一种低碳优质碳素结构钢,S、P杂质含量比普通碳素结构钢要低些,一般在0.035%（质量分数）以下。具有塑性、韧性、延展性、可塑性都是比较好的,由于它的含碳量低（在0.12～0.16%之间）,所以强度、硬度比较低。锻造、焊接和冷冲压性能良好,冷变形塑性高,但切削加工时不易得到光洁的表面。也由于含碳量低,这样的材料制成的零件要通过热处理提高硬度比较困难。需要加热到1100℃以上淬火才能获得较高硬度,一般的钡盐浴炉加不到这么高的温度,需要用高温硝酸盐浴炉来加热。     

锻造工艺对TC11饼材显微组织的影响

采用2种自由锻工艺制取TC11钛合金饼坯和饼材，测试了它们的窜温和高温力学性能。对2种工艺饼坯和饼材，从边部到心部，采用金相显微镜对其组织结构进行了观察分析，并用超声探伤仪检查组织缺陷，根据超声杂波水平评价和对比组织均匀性。通过检测获得了锻造工艺与性能关系的评细信息。实验结果得出，2种锻造工艺所制得的TC11饼材力学性能均符合GJB2220标准。其中一种工艺制取的饼材性能比另一种工艺饼材性能更为优越。     

超导用Nb55Ti饼材热处理工艺研究

对尺寸为?180 mm×30 mm的Nb55Ti钛合金饼材进行热处理试验,研究了不同热处理工艺对Nb55Ti钛合金饼材显微组织及力学性能的影响。选用的饼材原始组织是经过多火次锻造的均匀等轴组织。将此Nb55Ti钛合金饼材在750～900℃进行热处理试验。结果表明,随着温度的升高,Nb55Ti合金饼材的强度逐渐下降,但其伸长率和断面收缩率上升,断面收缩率甚至达到90%。     

Ti6242S钛合金盘形锻件锻造及热处理工艺研究

采用260 mm钛合金棒材,以锤锻和压机锻造的方式试制了Ti6242S饼坯和盘形锻件,研究了锻造及热处理工艺对显微组织、力学性能以及超声检测杂波水平的影响。结果表明:压机锻出的饼坯组织和性能更优;随着固溶温度的升高,锻件初生α相减少,杂波降低;经制坯、压机锻造、热处理,锻件可获得较优的组织和性能。     

TC4钛合金全面性能测试

TC4(Ti—6Al—4V)钛合金有优越的综合性能,在航空工业得到广泛的应用,世界各国对此合金都进行了大量研究工作,达到较成熟的阶段。随着我国航空工业的发展要求,我所对TC_4合金进行了全面和深入的研究,包括铸锭熔炼、锻造开坯、棒材挤压、热处理工艺、亮条组织、再结晶、饼材锻造和盘件模锻等项研究工作。在此研究的基础上,确定工艺、组织和性能三者之间关系,以使挤棒工艺稳定,性能可靠。     

SiC颗粒增强金属基复合材料成形性能研究

对一种ＳｉＣ颗粒增强铝合金基复合材料的锻造和挤压成形性能进行了研究，绘制了该材料的锻造成形极限图。研究了塑性成形对该材料微观组织的影响和成形的力能变化规律，结果表明：该材料的塑性变形是通过基体的塑性变形来实现的；在热变形时，ＳｉＣ颗粒能够通过转动来调整方位，形成沿金属流动方向的定向分布；塑性成形有助于细化ＳｉＣ颗粒，促进颗粒的均匀分布；材料在热锻时存在一强化极限，与此强化极限对应的变形程度随锻造温度的降低而增大；材料的成形极限与变形温度和变形速度等条件有关。     

节约能源有效方法之一——锻造余热淬火工艺

本文概述锻造余热淬火工艺是一种塑性加工与热处理工序连接在一起的新型技术,介绍锻造余热淬火工艺的特点,阐明各工艺参数对零件性能的影响及选择原则。最后还叙述锻造余热淬火钢的机械性能、显微组织和切削加工性能。     

自由锻造CAPP网络系统开发

1概述自由锻造是一种通用性很强的工艺方法，适用于生产用途不同、重量和尺寸变化范围大、各种复杂程度的锻件。按照锻件分类其锻造工艺为：饼类银件的基本工序是激粗；环、圈、套、简类锻件的基本工序是锻孔，机床主轴、轧辊等轴类锻件的基本工序是拔长或撤粗一拔长；吊钩等弯曲件的基本工序是弯曲；各种曲轴的基本工序是错移和扭转等。锻造工艺过程包括：①根据零件图作出锻件图。②确定毛坯重量和尺寸.③决定变形工艺及工具。④选择设备。⑤确定锻造温度范围、火次及冷却方式。⑥确定热处理规范。⑦对锻件提出技术和检验要求。随着CAD…     

β锻造Ti-6Al-4V合金力学性能各向异性（英文）

研究β锻造Ti-6Al-4V(Ti64)合金拉伸性能和断裂韧性的各向异性。对饼材不同取向的显微组织和晶体学织构进行分析，同时研究取样方向对拉伸性能、断裂韧性的影响。结果表明，Ti64饼材原始β晶粒呈扁平状。室温下合金主要由α相构成，β锻造后β→α相变产生的多个α相变体导致α相织构强度较低。力学性能各向异性的主要影响因素为原始β晶粒形貌以及与α织构相关的滑移。采用J积分阻力曲线法测定合金的起裂韧性，并将起裂韧性KJIC分为内在韧性和外在韧性。内在断裂韧性各向异性主要与原始β晶粒对裂纹尖端塑性区范围的影响相关；外在断裂韧性主要与α片层与集束对裂纹曲折程度的影响相关。     

眼镜架用Ti-22V-4Al合金丝制备工艺研究

Ti—422（Ti-22V-4Al）合金具有优越的综合性能，特别具有很好的冷加工成形性，因此，用于制作高端眼镜架极具潜力。为了获得规模化生产Ti—422合金眼镜丝材的最佳工艺，对该合金冷加工丝材的变形程度和热处理工艺同力学性能和组织结构的关系进行了研究。结果得出，采用Ф10mm热轧坯料，辊模拉拨到4,5．0mm，退火后按55％～70％变形再辊模拉伸制得不同直径的丝材料，经7800C，30min退火处理，其组织均匀，延伸率达20％以上。然后经520℃，4h时效处理，维氏硬度达到2800MPa，完全达到眼镜架用丝材对材料硬度2700MPa〈HV〈3000MPa的技术要求。     

连续胞状结构强化Ta-W-Hf合金的压缩变形

采用粉末冶金法制备了具有连续胞状强化结构的致密Ta-W-Hf合金材料,通过压缩试验研究了这种高强度材料的塑性变形特征,以了解其进一步变形加工的可能性.结果表明,连续胞状结构强化Ta-W-Hf材料与传统熔炼加工材的压缩变形特征没有大的区别,各试样均可承受50%以上的冷压缩变形,而无宏观裂纹产生.试样的硬度随着压缩变形量的增加而增大,但高温退火试样的硬度增量远大于热等静压试样,故其具有更大的形变强化容量.     

Effect of chromium on the mechanical properties of powder-processed Fe–0.45 wt.% P alloys

The present investigation shows the role of chromium in Fe–P binary and Fe–P–Cr ternary alloys. The compositions are characterized in terms of microstructure, porosity content, hardness and tensile properties. The alloys were made using a hot powder forging technique. In this process mild steel encapsulated powders were hot forged into slabs. Then the slabs were hot rolled and annealed to relieve the residual stresses. Densifications as high as 98.9% of theoretical density have been realized. Microstructures of these alloys consist of single-phase ferrite only. Both Fe–0.45P and Fe–0.45P–3Cr alloys showed very high strength. As forged and hot rolled Fe–0.45P alloy showed low elongation. It was observed that, the addition of Cr to Fe–P based alloys caused an increase in strength associated with the reduction in ductility. Alloys developed in the present investigation were capable of hot working to very thin gage of sheets and wires.     

PM René 95合金涡轮盘等温锻造工艺的模拟式设计

利用热力耦合有限元程序FORMT,对PM　Rene95合金中等尺寸（外径尺寸约为630mm）涡轮盘的等温锻造工艺进行了模拟式设计.结果表明,采用TZM钼基合金模具。在1050℃以接近10-3s-1的应变速率进行闭式模锻和开式模锻,模具材料均能满足使用要求,且开式模锻设备最大载荷不超过31×103kN;采用K21合金模具,在1000℃以相同条件等温成形。模具材料因变形热效应及边界摩擦引起温升而失效且所需设备吨位相对较大.     

Effect of tungsten content on microstructure and quasi-static tensile fracture characteristics of rapidly hot-extruded W-Ni-Fe alloys

Tungsten heavy alloys (WHAs) with three different compositions (90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe and 95W-3.5Ni-1.5Fe, wt.%) were heavily deformed by one-pass rapid hot extrusion at 1100 °C with an extrusion speed of ~ 100 mm/s and an extrusion ratio of ~ 3.33:1. The influence of tungsten content on the microstructure and tensile fracture characteristics of the as-extruded alloys was investigated in detail. The results show that the tungsten particles in the as-extruded 95W have the largest shape factor compared to the as-extruded 90W and 93W alloys and this implies that the tungsten particles in the as-extruded 95W alloy were subjected to the heaviest plastic deformation. In addition, ultimate tensile strength (UTS) and hardness (HRC) are significantly improved after rapid hot extrusion. The as-extruded 95W alloy processes the highest strength (1455 MPa) and hardness (HRC40) but the lowest elongation (5%), followed by the as-extruded 93W (UTS1390MPa; HRC39; 7%) and 90W alloys (UTS1260MPa; HRC36; 10%). The fracture morphology shows the distinct fracture features between the as-sintered alloys and the as-extruded alloys. For the as-sintered alloys, the fracture modes are various while transgranular cleavage of tungsten particles is the main characteristic in the as-extruded alloy. Meanwhile, the fracture modes of the three as-extruded alloys vary slightly with the tungsten content. TEM bright field images indicate that many lath-like subgrains with the width of 150-500 nm are present in the three as-extruded alloys, particularly in the as-extruded 93W and 95W alloys. Furthermore, the dislocations are absent in the γ-(Ni, Fe) phase. This means that dynamic recovery-recrystallization process took place during rapid hot extrusion.     

Impacting Behavior of Large Oxidized Copper Particles in Cold Spraying

In a previous study, it has been experimentally demonstrated that surface oxide films of metallic particles have significant influence on the properties of cold-sprayed coatings. To clearly reveal the underlying mechanism, this study focused further on the effect of particle oxidation on the deposition behavior of oxidized Cu powder. Results show that the presence of the oxide films on the particles’ surface can inhibit the plastic deformation of the particles. In addition, results concerning the morphologies and oxygen content of the rebounded particles show that the particles have experienced large plastic deformation that results in the break-up of the oxide films during the impacting process. Correspondingly, the hardness of the coating deposited with the oxidized powder is a little lower than that with the annealed powder because of the inferior plastic deformation and strain-hardening effect.     

烧结方式对CoCrNi中熵合金组织及力学性能的影响

采用机械合金化法（MA）球磨制备CoCrNi中熵合金原料粉末,结合放电等离子烧结（SPS）或高真空烧结制取CoCrNi中熵合金,研究了球磨时间以及退火对CoCrNi中熵合金原料粉末微观形貌、颗粒尺寸及相结构的影响规律,对不同烧结方式制备的合金块体进行微观结构及力学性能研究。结果表明：随着球磨时间的延长,各单质粉末颗粒尺寸不断减小并逐渐融合,在球磨25 h后,原料粉末主要为fcc固溶体结构,还有少量的bcc相;在后续烧结过程中,少量bcc相发生相转变,组织中只有fcc相结构;退火烧结样品的弹性模量为6.57 GPa,是真空烧结的1.55倍,屈服强度为279.28 MPa,与真空烧结后样品的屈服强度相当,退火烧结的延伸率为35.97%,明显大于直接真空烧结;SPS烧结的块体合金表现出高达793.72MPa的屈服强度和61.08%的塑性应变,且维氏硬度(HV)达到3910.2MPa,与其它2种烧结方法相比,SPS在实现高熵合金（HEAs）快速低温烧结方面更具潜力。     

Investigation of Impact Behavior of Cold-Sprayed Large Annealed Copper Particles and Characterization of Coatings

In this research, the large gas-atomized copper powder was selected as the feedstock. Some powder was annealed in a vacuum circumstance to avoid the effect of grain boundaries on the high velocity impact behavior of particles during cold spraying. The annealed Cu powder was deposited by cold spraying with respect to the single impacts and coating deposition under certain gas condition. In addition, the rebounded copper particles were collected for morphology analysis compared to the adhered particles. The results show that the average size of the rebounded particles is apparently increased compared with the starting powder because of the rebounding of larger particles and intensive plastic deformation of the rebounded particles. For the deposited particles, obvious plastic deformation causes a higher hardness to the coating. It is found that the rebounded particles have also experienced large deformation and shear instability at the impact interfaces.     

纯铁在高应变率下的流动应力特征及其动态塑性本构关系

利用MTS材料试验机和分离式Hopkinson压杆实验装置,对锻造后经930℃下退火2h的纯铁材料进行压缩实验,测定纯铁在准静态条件(10-3s-1~100s-1)和高应变率(650s-1~8500s-1)下的应力-应变曲线。实验结果表明,纯铁是应变率敏感材料,纯铁在高应变率条件下,具有应变率增强、增塑以及应变强化效应,高应变率下的塑性变形过程中产生的绝热升温对材料具有热软化作用。基于Johnson-Cook(J-C)本构模型,引入绝热温升软化项对模型进行修正,通过实验数据拟合得到了纯铁的动态塑性本构关系,模型计算结果和实验结果证明,该模型可以较好地预测纯铁在高应变率下的塑性流动应力。     

Age Hardening of AlCrMoNiTi High Entropy Alloy Prepared by Powder Metallurgy

采用粉末冶金工艺制备了AlCrMoNiTi高熵合金,并对其铸态和退火态的微观组织和硬度进行了研究。结果表明,铸态合金由富(Cr,Mo)bcc固溶体枝晶相和富(Al,Ni,Ti)fcc固溶体枝晶间相组成。时效合金在900℃高温可获得最高硬度HV约为6150 MPa,在1000℃发生退火软化现象,但是其硬度HV仍保持在5160 MPa的高硬度水平。这表明,AlCrMoNiTi高熵合金具有优异的高温时效硬化特性。该合金在800℃时的时效硬化特性主要归因于细晶强化,在900℃时则归因于第二相(bcc2)的析出硬化。在1000℃时发生退火软化现象,其原因在于第二相的分解和晶粒粗化。     

Constitutive Relationship of IN718 Alloy for Thermoviscoplastic and Microstructure Evolution Coupled Analysis

The interaction between thermomechanical parameters and microstructure evolution is so intense that it must be considered during the finite element method (FEM) simulation of the hot plastic working process, for materials that are difficult to deform. Taking the microstructure evolution into account, a novel type of constitutive relationship has been put forward for the IN718 alloy. The microstructure evolution model was first established for the dominant microstructure evolution processes. Then the microstructure evolution models and the method to determine the local flow stress of the corresponding microstructure for current thermomechanical parameters and deformation history were presented. Once the local flow stresses of different structures and their volume contributions were defined, the apparent flow stress of the material could be determined as the weighted sum of the local flow stresses and volume contributions. To validate the proposed method, a thermoviscoplastics and microstructure evolution coupled analysis for a forging process of a critical IN718 disk forging was performed. The predicting results were in close agreement with the experimental data.