Study on Combination Forming of Liquid Forging and Following Extrusion and Rolling of Ceramic Particulate Reinforced Aluminium Alloy Plate

对陶瓷粒子向铝液或铝粉混合过程机制和均匀性进行了研究,发现搅融混合实用性强,均匀性差,而原位反应法和粉末混合法能获得均匀浆料或粉末体。自行设计和制造了液锻连挤和固液挤压板坯的实验装置,进行了不同类型混合粉挤压成形的研究,从而揭示了液锻连挤和固液挤压工艺的实质,使其获得的板坯具有较好的塑性。再轧制实验,获得了不同开轧温度和轧制压下量对组织性能影响数据。搅融混合硅线石颗粒与LY12,经固液挤压或液态模锻加工连杆瓦和轴瓦,以替代锡青铜,并通过实际考核,具有明显降噪、减振和抗磨性。     

机械合金化改性硫化亚铁/铜合金粉末的特性

为了解决FeS/Cu粉末冶金复合材料中FeS易团聚以及界面结合差的问题,采用机械合金化技术制备了FeS/Cu复合材料粉末。利用扫描电镜、X射线衍射仪、金相显微镜等对不同球磨时间的质量分数为6%的FeS/Cu合金粉末的混合特性、压制特性及烧结后的力学性能进行检测和分析,结果表明：机械合金化可有效改善FeS颗粒与基体合金粉末的混合均匀性,烧结后材料的密度、硬度均得到提高,FeS和Cu界面结合良好;由于FeS颗粒均匀弥散地分布在铜合金基体中,割裂了基体材料的连续性,反而使复合材料的韧性和压溃强度有所降低。     

常州一步药用多功能制粒包衣机成功应用于制药生产

正常州一步干燥设备有限公司研发生产的药用多功能制粒包衣机具有混合、制粒、包衣、干燥、冷却等功能,其适用范围比较广,特别是在制药生产中取得了成功的应用。该药用多功能制粒包衣机将喷雾干燥制粒、流化床、喷动流化床以及旋转造粒等技术有机地结合为一体,可以均匀地混合流态化的物料,如粉末、颗粒、微丸等。其中,利用空气的多向运动(如水平、射线和切线方向),可均匀混合物料;通过喷射黏合剂于粉末状物料,可以制得各种颗粒;物料底喷系统采用三层结构喷嘴,为粉末、颗粒或微     

IN718镍基高温合金粉末的铺粉均匀性

在不同刮板移动速度(28.23,63.55,91.11,125.25 mm·s^-1)下对IN718镍基高温合金粉末进行铺粉，粉层厚度分别为0.3,0.5,0.7,0.9 mm。采用自制铺粉均匀性测试装置收集粉层不同位置相同体积的粉末并称取其质量，通过计算质量标准差研究了刮板移动速度和粉层厚度对铺粉均匀性的影响。结果表明：粉层的质量标准差随刮板移动速度或粉层厚度的增加而增大，说明铺粉均匀性变差，刮板移动速度对铺粉均匀性的影响更大；获得最佳铺粉均匀性的工艺参数组合为刮板移动速度28.23 mm·s^-1、粉层厚度0.3 mm。     

新型纳米合金粉技术在沈阳问世

沈阳泰普纳米公司日前发明了用喷雾自蔓延热解技术合成纳米合金粉的新工艺。该工艺流程主要是将可溶性金属盐和无机盐溶于水中，使金属元素在分子水平上均匀混合，制成前体水溶液；将上述前体水溶液进行干燥处理，制成前体或前体粉末；在空气、氧气、氮气或所述气体混合气氛下加热前体或前体粉末，采用自蔓延热解法除去可溶性盐的其他离子，制成中间体粉末；在固定床或流动床中，在流动氢气气氛下通过热化学对中间体粉末进行还原处理。该技术是中国知识产权专利技术，具有低成本、低反应温度、综合性能高、无有害气体产生等优点。使用纳米级…     

以TiH2为造孔剂的球磨铁基含油材料孔隙表征及其摩擦学性能

以Fe、C混合粉末为原料,TiH_2粉末为造孔剂,通过高能球磨工艺使各粉末混合均匀,以普通粉末冶金工艺方法制备含油铁基轴承材料。用HDM-20端面摩擦磨损试验机在干摩擦工况下考察材料摩擦磨损性能,使用Image J图像分析软件对材料孔隙进行表征,用VK-S105三维轮廓扫描仪观察磨痕3D形貌,利用扫描电镜观察粉末微观形态及样品截面孔隙形态。实验结果表明:随着TiH_2粉末含量增加,铁基烧结材料基体孔隙增多;球磨工艺下,基体表面孔隙大小均匀,孔隙连通性改善,材料含油率升高,摩擦学性能优良;当TiH_2质量分数为2%时,材料摩擦因数较低,磨损量较少,摩擦因数波动较小,有较长时间的平稳运行过程。     

燃料相体积分数对U-Mo/Al弥散型燃料板的铀分布均匀性影响

采用原有混合工艺对20%~30%燃料相体积分数的U-Mo微球和铝粉进行混合后,制备成燃料板,分析燃料板的铀分布均匀性,获得燃料相体积分数对铀分布均匀性的影响规律。燃料板的铀均匀性采用γ射线吸收法进行检测。检测结果表明,在20%~26%燃料相体积分数范围内铀分布均匀,当燃料相体积分数增加到28%以上时,铀分布均匀性逐渐变差。在此基础上,对原有混合工艺不适用的燃料相体积分数进行混合工艺参数优化。燃料相体积分数为28%和30%的混合工艺经优化后,铀分布均匀性得到显著提升。     

浅谈硬质合金刀片的钎焊工艺

切削用的硬质合金刀片均为粉末合金制品,一般常用的有两类:一类是钨钴类(YGx)硬质合金;另一类是钨钴钛类(YTx)硬质合金。把这些碳化物合金粉末经细磨、搅拌均匀后,放进模具冷压烧结或热压成形。冷压时,为了减小合金粉末之间、合金粉末与模壁之间的摩擦,使压制出来的刀片致密均匀,在压制前对合金粉末进行掺胶或掺蜡处理,压     

固液混合铸造Al-10Cr合金的耐磨损性能

采用固液混合铸造新技术制备了Al-10Cr合金,并对其显微组织和耐磨性进行了研究.结果表明：固液混合铸造能明显细化Al-10Cr合金的析出相,使其均匀圆整,所制备的合金耐磨性特别是高温耐磨性能优于传统铸造和半固态铸造合金;粉末粒度为74～175 μm、粉末与熔体的质量比为0.4时,合金的磨损率最小;室温干滑动磨损机制主要为磨粒磨损,高温干滑动磨损机制则主要为磨粒磨损和粘着磨损相结合.     

陶瓷材料工件的车削

一、陶瓷材料工件的成型陶瓷材料有三种 ,(1)氧化物陶瓷如Ａｌ2 Ｏ3;(2 )非氧化物陶瓷如ＳｉＮ2 、ＳｉＣ ;(3)混合物陶瓷如Ａｌ2 Ｏ3 ＳｉＮ2 。陶瓷材料的毛坯可用粉末冶金方法制造 ,将陶瓷粉末混合后压制成型 ,其形状只是接近成品的毛坯 ,然后焙烧———机械加工 (一般是粗加工 )———烧结———(精加工 )车削或磨削加工。我单位曾承接某大学的十多套不同规格的模具 ,其中一种模具零件如图 1所示 ,模具的材料属于混合陶瓷材料 ,其成分是ＺｒＯ2 (70 %～ 80 % )、Ａｌ2 Ｏ3(2 0 %～30 % ) ,用混料机将两种粉末混合均匀 ,放在一个橡胶制成…     

Effects of Morphological Characteristics of Alumina Particles and Interfacial Bonding Strength on Wear Behavior of Nano/Micro-alumina Particulates Reinforced Al/A206 Matrix Composites

Matrix/reinforcement interface has a critical role in determining the properties of metal matrix composites (MMCs). Properties of matrix/reinforcement interface depend on the fabrication method. The main problem in the fabrication of MMCs is wettability between reinforcing particles and molten alloy. Al206/5 vol% alumina_p cast composites were fabricated by the addition of reinforcing particles into molten Al alloy, semi-solid and liquid states, in two different forms: (1) as-received alumina (nano/micro) particles and (2) pre-synthesized composite reinforcement prepared via ball milling of alumina (nano/micro) with Al and Mg powders (master metal matrix composite). The effects of powder addition techniques, alumina/matrix interfacial bonding strength, and morphological characteristics of alumina particles on wear behavior were investigated. A new combination parameter, called alumina particle appearance (APA) index, was introduced. APA index approximates the collective effects of morphological characteristics of alumina particles on wear behavior. It is suggested that samples with lower APA index have superior wear properties. Microscopic examinations of the composite and matrix alloy and alumina/matrix interface were studied by scanning electron microscopy and transmission electron microscopy. It was found that wear resistance was increased in the composites fabricated by the addition of pre-synthesized reinforcing particles into molten alloy in the semi-solid state. Improvement in wear resistance is attributed to higher bonding strength of matrix/reinforcement as well lower APA index compared to those prepared via as-received alumina particles.     

SiCP/2024复合材料在半固态下流变行为的研究

采用半固态等温压缩试验和金相显微镜等方法和手段,对SiCP/2024复合材料在半固态下流变行为进行了研究。结果表明,SiCP/2024复合材料在半固态下压缩时的流动应力随试验温度的提高而显著下降;当压缩时间较短时,复合材料的压缩应力比未增强合金小,当压缩时间较长时,压缩应力大于未增强体合金,且其具有伪塑性体的特性。     

Influence of graphite content on the dry sliding and oil impregnated sliding wear behavior of Al 2024–graphite composites produced by in situ powder metallurgy method

The influence of graphite content on the dry sliding and oil impregnated sliding wear characteristics of sintered aluminum 2024 alloy–graphite (Al/Gr) composite materials has been assessed using a pin-on-disc wear test. The composites with 5–20 wt.% flake graphite particles were processed by in situ powder metallurgy technique. For comparison, compacts of the base alloy were made under the same consolidation processing applied for Al/Gr composites. The hardness of the sintered materials was measured using Brinell hardness tester and their bending strength was measured by three-point bending tests. Scanning electron microscopy (SEM) was used to analyze the debris, wear surfaces and fracture surfaces of samples. It was found that an increase in graphite content reduced the coefficient of friction for both dry and oil impregnated sliding, but this effect was more pronounced in dry sliding. Hardness and fracture toughness of composites decreased with increasing graphite content. In dry sliding, a marked transition from mild to severe wear was identified for the base alloy and composites. The transition load increased with graphite content due to the increased amount of released graphite detected on the wear surfaces. The wear rates for both dry and oil impregnated sliding were dependent upon graphite content in the alloy. In both cases, Al/Gr composites containing 5 wt.% graphite exhibited superior wear properties over the base alloy, whereas at higher graphite addition levels a complete reversal in the wear behavior was observed. The wear rate of the oil impregnated Al/Gr composites containing 10 wt.% or more graphite particles were higher than that of the base alloy. These observations were rationalized in terms of the graphite content in the Al/Gr composites which resulted in the variations of the mechanical properties together with formation and retention of the solid lubricating film on the dry and/or oil impregnated sliding surfaces.     

Effects of electromagnetic stirring and rare earth compounds on the microstructure and mechanical properties of hypereutectic Al–Si alloys

In this paper, the effects of rare earth addition and electromagnetic stirring on the microstructure and the mechanical properties of hypereutectic Al–Si alloys have been reported. Hypereutectic Al–Si alloy was prepared using liquid metallurgy route and modified with the addition of cerium oxide. To control the structure, slurry of hypereutectic Al–Si alloy was subjected to electromagnetic stirring before pouring into the mould. It was observed that the addition of cerium oxide (0.2 wt.%) refined the primary silicon particles and modified the eutectic silicon particles. Further, the electromagnetic stirring of the hypereutectic Al–Si alloy reduced the average size of primary silicon particles, from 152?±?9 to 120?±?6 μm, and the length of β-intermetallic compounds decreased from 314?±?12 to 234?±?10 μm. Similarly, the application of electromagnetic stirring on cerium oxide-modified hypereutectic Al–Si alloy also reduced the average size of primary silicon particles from 98?±?5 to 76?±?4 μm and the average length of β-intermetallic compounds from 225?±?7 to 203?±?5 μm. Mechanical properties namely tensile strength, ductility and hardness of the alloys were improved with electromagnetic stirring and addition of cerium oxide appreciably.     

镁合金半固态成形的现状及发展前景

阐述镁及镁合金的特性。从非枝晶坯料的制备、坯料的重熔加热和半固态的成形工艺等三方面介绍镁合金半固态成形的研究现状。详细介绍采用机械搅拌法、电磁搅拌法、应变诱发熔化激活法(Strain-induced M elt ActivationProcess,SIMA)和半固态等温热处理法制备非枝晶坯料的最新研究成果。展望我国镁合金半固态成形技术的发展前景。     

用铝粉作增粘剂制备泡沫铝

采用熔体发泡法制备了孔结构均匀、孔隙率高的泡沫铝材料,系统研究了铝粉(增粘剂)含量、增粘搅拌时间、保温时间和发泡剂的含量对孔隙率和孔结构的影响。对铝粉在铝熔体中的增粘机理以及在发泡过程中对气泡的稳定作用进行了讨论。结果表明:加入质量分数5％铝粉,搅拌时间7 min,发泡剂TiH2质量分数1．5％,保温5 min的条件下,可以得到孔结构均匀、孔隙率约75％的泡沫铝硅合金材料。     

反应合成法制备Al_2O_3/Al复合材料

采用搅拌方法加入 Cu O粉末与 Al液进行原位反应 ,并用铸造工艺成功制备了 Al2 O3 /Al复合材料。试验结果表明 :Cu O粉末与 Al液能原位反应生成 Al2 O3 ,反应有一较长的孕育期 ,生成的 Al2 O3 细小且均匀分布在 Al基体上 ,具有强烈的增强效果 ,复合材料的硬度远高于基体材质     

反应合成法制备Al2O3／Al复合材料

采用搅拌方法加入CuO粉末与Al液进行原位反应,并用铸造工艺成功制备了Al2O3/Al复合材料,试验结果表明：CuO粉末与Al液能原位反应生成Al2O3,反应有一较长的孕育期,生成的Al2O3细小且均匀分布在Al基体上,具有强烈的增强效果,复合材料的硬度远高于基体材质。