放电等离子烧结制备亚微米LaB6块体材料

采用氢直流电弧等离子体法,以稀土镧块为原料,制备出了平均粒度为20 nm的La纳米粉末.以L丑纳米粉和B纳米粉为原料,采用放电等离子烧结(SPS)技术制备出了LaB6亚微米晶块体材料.通过系统研究各烧结参数对材料结构和性能的影响,得到了最佳的烧结工艺.获得了相对密度高达99.3%的致密烧结体,其维氏硬度达到14.1 GPa.采用XRD,SEM和TEM对材料的相组成和微观组织进行了测试分析.结果表明.SPS烧结LaB6块体的晶粒细小,平均晶粒尺寸为150nm,整体结构均匀致密.实验表明,SPS技术可以实现LaB6细晶块体材料的快速烧结.     

W-Re高比重合金的SPS烧结

采用放电等离子烧结(SPS)设备制备了W-Re高比重合金,烧结温度为1800℃,烧结压力为40MPa,保温时间为5min。对SPS烧结的W-Re合金试样进行了密度、硬度等性能测试。采用金相显微镜观察试样的金相组织、晶粒大小。结果表明:采用SPS烧结,可以在较低的温度下实现W-Re合金的致密化,并能有效控制晶粒长大,提高材料的硬度。     

SPS法制备Al2O3/Cu复合材料研究

将纳米级A12O3以体积分数为1％的配比与微米级Cu粉混合均匀后,采用放电等离子烧结(SPS)法,分别在750、800和850℃进行烧结制备复合材料;将同样的混合粉末采用冷压烧结制备复合材料作为对比.分别测试材料的密度、硬度、导电率,并进行SEM扫描电镜分析.结果表明:在所选择试验参数下,烧结温度为800℃ SPS烧结试样具有最高的相对密度,达到99.17％,硬度与导电率也最高;与冷压烧结制备的材料相比,SPS法制备的试样硬度和导电率更高;SPS烧结试样晶粒均匀细小,并出现了孪晶.     

放电等离子体烧结工艺对La_(0.7)Fe_3CoSb_(10)材料相对密度的影响

用熔炼-退火-放电等离子体烧结法(SPS)制备了晶粒尺寸均匀的La0.7Fe3CoSb10材料.采用扫描电镜,研究了SPS工艺,包括粉末粒度、烧结温度及烧结时间对该材料相对密度的影响.结果表明:烧结试样的相对密度随烧结时间的延长和温度的升高而增高;通过控制退火温度可有效地控制材料最终的晶粒尺寸.     

机械球磨与放电等离子体烧结制备碳纳米管/铜复合材料

采用机械球磨和放电等离子体烧结(SPS)工艺制备了碳纳米管(CNTs)/铜复合材料.利用SEM和TEM对材料组织和形貌进行了表征,研究了球磨时间、CNTs含量、SPS烧结压力对复合材料组织和性能的影响.结果表明:质量分数为1％的CNTs可在铜基体中获得良好分散;CNTs与铜基体界面结合良好,有利于应力在基体与CNTs之...     

放电等离子烧结技术

综述了放电等离子烧结(SPS)技术在国内外的发展概况,深入探讨了SPS的烧结机理.介绍了SPS技术在制备纳米材料、梯度功能材料和高致密度、细晶粒陶瓷等方面的研究和应用.展望了SPS技术的发展前景.     

大块非晶合金的制备、性能与应用研究进展

大块非晶舍金由于其独特的结构和优异性能而得到广泛的研究。本文从大块非晶合金的制备原理和工艺、性能以及应用三方面详述了大块非晶研究概况和进展，并针对存在的问题提出了建议，最后提出了今后大块非晶发展的方向。     

大块非晶体材料的研究发展

综合评述了大块非晶体材料的发展历史及研究现状 ,详细介绍了大块非晶合金的结构、性能与应用以及形成非晶合金的热力学条件、结构条件、以及动力学条件。同时还简单介绍了熔体水淬法、爆炸焊接法等制备技术     

烧结温度对SPS制备Ag/La2O3触点材料的影响

采用放电等离子烧结(SPS)技术制备了Ag/La2O3触点材料,研究了烧结温度对其致密度、显微结构及力学性能的影响.结果表明:采用SPS技术制备Ag/La2O3触点材料的工艺中,烧结温度对材料的致密度有着显著的影响,500℃烧结体的致密度最大,达到了97.2%,且试样的抗弯强度最高,约为450MPa;塑性断裂是其主要断裂方式,在不同烧结温度的烧结过程中没有新相出现,La2O3颗粒在银基体中均匀弥散分布.     

Al85Ni5Y10非晶粉末及合金的制备研究

本文采用自行设计的快速冷凝装置制得了非晶Al_(85)Ni_5Y_(10)合金粉末,并对非晶粉末的性能进行了研究。将非晶粉末通过爆炸成形、真空热压和挤压成型三种工艺进行固结和热致密化,分别得到了基本非晶、部分非晶和微晶三种大块Al_(85)Ni_5Y_(10)合金,对三种材料的性能进行了测试。     

发动机用石墨烯增强TC11合金放电等离子烧结制备参数优化及力学性能研究

通过添加石墨烯提高了放电等离子烧结（spark plasma sintering, SPS）制备发动机用耐高温TC11合金的力学性能,研究了不同烧结参数下TC11合金的密度,并观察了合金显微组织,分析了合金力学性能的影响因素。研究结果表明:随着烧结温度增加,试样密度先增加后平稳;提高烧结压力后,试样密度发生了略微上升。随着烧结温度的上升,更多α相转变成了高温β相,形成了相对稳定的β相比例。随着烧结时间的增加,合金室温压缩强度表现为升高的趋势。提高烧结压力后,TC11合金获得了更高的室温与高温力学强度。通过实验最终确定烧结时间5 min、温度900 ℃与压力50 MPa时制备的TC11合金具有最优力学性能。     

Bulk nanocrystalline aluminum 5083 alloy fabricated by a novel technique: Cryomilling and spark plasma sintering

Dense, bulk nanocrystalline aluminum 5083 alloy was fabricatedvia a combined technique: cryomilling (mechanical milling at cryogenic temperature) to achieve the nanocrystalline Al 5083 powder and spark plasma sintering (SPS) to consolidate the cryomilled powder. The results of X-ray diffraction analysis indicate that the average grain size in the SPS consolidated material is 51 nm, one of the smallest grain sizes ever reported in bulk Al alloys produced by powder metallurgy derived methods. In contrast, transmission electron microscopy (TEM) analysis revealed a bimodal grain size distribution, with an average grain size of 47 nm in the fine-grained regions and approximately 300 nm in the coarse-grained regions. Nanoindentation was used to evaluate the mechanical properties and the uniformity of the consolidated nanocrystalline Al 5083. The hardness of the material is greatly improved over that of the conventional equivalent, due to the fine grain size. The mechanisms for spark plasma sintering and the microstructural evolution are discussed on the basis of the experimental findings.     

钼钨合金烧结致密化行为

采用原位测量法研究了放电等离子烧结与真空热压烧结Mo–30W合金收缩和致密化行为。研究结果表明:采用放电等离子烧结Mo–30W合金时，1200 ℃以下Mo–30W合金以膨胀为主，1200 ℃以上合金开始剧烈收缩，1600 ℃以上合金收缩趋于停止，在降温阶段合金有较大收缩，温度接近室温时，收缩基本停止。经过1600 ℃放电等离子烧结后合金的相对密度可达93%以上，优于相同温度下真空热压烧结合金的相对密度89.98%。     

Assessment of consolidation of oxide dispersion strengthened ferritic steels by spark plasma sintering: from laboratory scale to industrial products

Abstract

Oxide dispersion strengthened steels are new generation alloys that are usually processed by hot isostatic pressing (HIP). In this study, spark plasma sintering (SPS) was studied as an alternative consolidation technique. The influence of the processing parameters on the microstructure was quantified. The homogeneity of the SPSed materials was characterised by electron microprobe and microhardness. A combination of limited grain growth and minimised porosity can be achieved on semi-industrial compact. Excellent tensile properties were obtained compared to the literature.     

放电等离子烧结快速制备高钪含量铝钪合金

采用放电等离子烧结技术制备高钪含量Al-Sc合金,利用扫描电子显微镜、能谱仪和X射线衍射仪等设备对球磨前后Al-Sc合金粉末的形貌、相组成以及不同温度快速烧结样品的显微组织结构进行观察和分析,研究烧结温度对Al-Sc合金显微组织的影响。结果表明:球磨后粉末的形状较规则,其颗粒尺寸为25~45mm,并初步实现了机械合金化,除Al、Sc相以外,有少量Al3Sc和AlSc2相生成。放电等离子烧结可实现高钪含量铝钪合金的快速致密化,成功制备出钪含量30%(质量分数)的铝钪合金,通过调整烧结工艺参数,烧结样品的相对密度可达92.19%;当烧结温度高于500℃时,所得样品致密,无孔洞,且无明显晶界;随着烧结温度的提高,Sc相与第二相融合,形成Al3Sc、AlSc2等第二相,存在于合金中,且Al3Sc相呈现逐渐增强的趋势。     

Spark plasma sintering versus hot pressing – densification,bending strength,microstructure, and tribological properties of Ti5Al2.5Fe alloys

Ti5Al2.5Fe alloys were fabricated by the spark plasma sintering (SPS) and hot pressing (HP) pressure-assisted sintering techniques from pre-alloyed powders with a particle size of about 200?μm. The powders were sintered at 850 °C for two different holding times (5 and 8 min) and heating rates (50 and 150°C?min^?1) at 25?MPa. The maximum relative densities were 99.70 and 98.78% for SPS and HP samples, respectively. All the alloys prepared by the SPS process had significantly higher bending strengths (1825–2074?MPa) than the alloys prepared by the HP process (648–1330?MPa). A decrease in the heating rate from 150 to 50°C min^?1 enhanced the wear resistance of the Ti5Al2.5Fe alloys prepared by both the SPS and HP processes.     

Spark plasma sintering of Al-Si-Cu-Fe quasi-crystalline powder

This article presents the results of a study on the microstructure and mechanical properties of Al-Si-Cu-Fe specimens produced by the spark plasma sintering (SPS) technique. The microstructure of the starting powder and bulk specimens was analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The formation of the icosahedral and decagonal quasi-crystalline phases in the as-gas-atomized powders is described for the first time. It is then shown that these metastable phases transformed into the 1/1 cubic-approximant phase upon heating at about 600 °C. Second, the effects of SPS process parameters such as the temperature and time have been investigated. Owing to the generation of a spark discharge between neighboring powder particles, dense cylindrical samples were obtained after a short sintering time of 30 minutes at the temperature of 650 °C. The highest values of the Vickers microhardness, about 8.9 GPa, were obtained when the powders were sintered in the temperature range of 600 °C to 650 °C for a holding time of 30 minutes, while the fracture toughness was found to be inversely proportional to the sintering temperature. However, at the sintering temperature of 650 °C, the fracture toughness increased from about 1.40 to 1.52 MPa √m as the holding time increased from 10 to 60 minutes. As compared to cast specimens, the enhanced mechanical properties are explained by the refined microstructure resulting from the low temperature and short sintering time applied during SPS processing.     

Spark plasma sintering of Al-Si-Cu-Fe quasi-crystalline powder

This article presents the results of a study on the microstructure and mechanical properties of Al−Si−Cu−Fe specimens produced by the spark plasma sintering (SPS) technique. The microstructure of the starting powder and bulk specimens was analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The formation of the icosahedral and decagonal quasi-crystalline phases in the as-gas-atomized powders is described for the first time. It is then shown that these metastable phases transformed into the 1/1 cubicapproximant phase upon heating at about 600°C. Second, the effects of SPS process parameters such as the temperature and time have been investigated. Owing to the generation of a spark discharge neighboring powder particles, dense cylindrical samples were obtained after a short sintering time of 30 minutes at the temperature of 650°C. The highest values of the Vickers microhardness, about 8.9 GPa, were obtained when the powders were sintered in the temperature range of 600°C to 650°C for a holding time of 30 minutes, while the fracture toughness was found to be inversely proportional to the sintering temperature. However, at the sintering temperature of 650°C, the fracture toughness increased from about 1.40 to 1.52 MPa √m as the holding time increased from 10 to 60 minutes. As compared to cast specimens, the enhanced mechanical properties are explained by the refined microstructure resulting from the low temperature and short sintering time applied during SPS processing     

电火花烧结的发展趋势

电火花烧结技术是一种新型的快速烧结技术。具有升温速度快、烧结时间短、效率高等特点。它是通过瞬间高能脉冲电流使粉末颗粒之间产生等离子放电,烧结制成高性能材料或制件。该文综述了电火花烧结的设备、工艺特点和技术原理;分析了电火花烧结的工艺参数对所制得材料的结构和性能的影响;简要介绍了电火花烧结技术在新材料制备及合成中的应用;展望了电火花烧结技术的发展前景。