工艺参数对激光金属沉积铜钛合金复合材料的影响（英文）

为获得最佳设计方案,设计两种实验方案,通过改变工艺参数对铜钛合金复合材料进行激光金属沉积。从显微组织演变、硬度和力学性能三方面对所沉积的复合材料进行表征。结果表明:复合材料的显微组织由一次、二次和三次枝晶臂,针状组织和α+β共晶组织组成。两种实验方案结果表明,在激光功率为1200 W,扫描速率为1.2 m/min的条件下得到的样品E具有最高的硬度,其值为HV(190±42),但由于其脆性,因此出现一些横间裂纹;而在激光功率为1200 W、扫描速率为0.3 m/min条件下得到的样品B无裂纹产生,且其显微组织良好并含有较多的枝晶。得到的铜复合材料的应变硬化系数为3.35。     

激光熔化沉积微观组织原位光谱监测:以CoCrMoW合金为例

研究了激光熔化沉积CoCrMoW涂层的微观组织与发射光谱的关系,及不同激光功率的光谱信号与CoCrMoW涂层一次枝晶间距、显微硬度的关系。提出了一种新的光谱信号指数积分面积,由4条离散Cr I谱线计算出电子温度。结果表明,当激光功率从400 W增加到1000 W,平均一次枝晶间距由3.426 μm增加到7.420 μm,显微硬度HV_0.2由3461 MPa降低到3095 MPa。光谱的积分面积和电子温度随激光功率的增大而增大。涂层的一次枝晶间距与光谱信号呈正相关,而涂层的显微硬度与光谱信号呈负线性相关。与电子温度相比,积分面积在预测一次枝晶间距和显微硬度方面显示出更好的潜力。     

激光工艺参数对TiC增强钴基合金激光熔覆层组织及性能的影响

采用6 kW CO_2激光制备了含10%的TiC-钴基合金熔覆层,通过OM、SEM、EDS、XRD及显微硬度计,研究激光工艺参数对熔覆层显微组织、成分、物相及硬度变化的影响规律。结果表明,熔覆层主要由γ-Co、TiC/(Ti, W)C_(1-x)、Cr-Ni-Fe-C和少量的Cr_7C_3相组成,从基体表面到熔覆层表层,组织由细树枝晶→等轴枝晶→细树枝晶,TiC弥散分布于二次枝晶臂根部、顶端或一次枝晶臂上。随激光功率降低或扫描速率增加,熔覆层枝晶含量增加,枝晶间距呈现增大趋势,TiC含量显著增加,尺寸变小,分布更均匀,而TiC形貌从边缘平滑的近圆形向不规则多边形转变,TiC溶解再析出会抑制一次枝晶或二次枝晶生长。实验范围内,随激光功率降低或扫描速率增加,熔覆层表层硬度增加,最高硬度为1246.6 HV_(0.2),相对基体提升接近5倍。     

模具钢表面连续激光沉积TiN类薄膜的研究

利用波长为10.6 μm的CO2连续激光诱导化学气相沉积的方法,在模具钢基体上沉积TiN类薄膜.采用XRD、OM、SEM、EDS等手段分析薄膜的组织和相结构.实验表明,当激光功率为600W,扫描速度为2 mm/s时,通过H2、N2和TiC14之间的化学反应,在模具钢表面获得了均匀致密的枝晶组织,其显微硬度最高可达2500HV.     

碳钢上激光辅助沉积Co-285合金的组织与性能

利用激光辅助直接金属沉积技术在1018低碳钢上沉积Co-285单壁墙,并利用优化参数制得大面积沉积层.利用光学显微镜、附带能谱仪的扫描电镜、X射线衍射仪、显微硬度计和磨损试验机研究沉积单壁墙或沉积层的显微组织、成分、物相、横截面的显微硬度分布和耐磨性.结果表明:沉积的单壁墙无气孔和裂纹等缺陷,成形性能良好,且与基体形成冶金结合;单壁墙由枝晶和枝晶间共晶组成;所有工艺参数下单壁墙的硬度相差不大;当激光功率为0.8 kW、送粉率为8.6 g/min、扫描速度为0.375 m/min时,单壁墙硬度值最大,达到407HV0.5;在此参数下制得沉积层的组织与单壁墙的类似,其相组成为α-Co固溶体、富Cr的M_(23)C_6和Co_3W;磨损60min后,沉积层体积损失为1.4 mm~3;磨损机制为研磨磨损、粘着磨损和氧化磨损的混合磨损.     

激光烧结Ni基合金块体实验研究

采用直接激光金属烧结技术,烧结成形了WC颗粒增强Ni基合金块体,采用扫描电子显微镜、X射线衍射仪和显微硬度计对烧结块体在不同工艺参数(激光功率、扫描速率)下的微观形貌、成分和显微硬度进行了研究。结果表明,激光烧结Ni基合金块体的优化工艺参数为:光斑直径1.0 mm,扫描速率0.7 m/min,扫描间距1 mm,激光功率900 W,铺粉厚度0.20 mm。激光烧结性能较好,WC颗粒熔化为枝晶且均匀分散在基体中,增强颗粒能被固液界面捕捉,提高了烧结块体的性能。物相组成主要有γ-Ni和WC颗粒,显微硬度值最高达到1110 HV。     

模具钢表面连续激光沉积TiN类薄膜的研究

利用波长为10．6gm的CO2连续激光诱导化学气相沉积的方法，在模具钢基体上沉积TiN类薄膜。采用XRD、OM、SEM、EDS等手段分析薄膜的组织和相结构。实验表明，当激光功率为600W，扫描速度为2mm／s，通过H2、N2和TiCl4之间的化学反应，在模具钢表面获得了均匀致密的枝晶组织，其显微硬度最高可达2500HV。     

模具钢表面连续激光沉积TiN类薄膜的研究

利用波长为10.6mm的CO2连续激光诱导化学气相沉积的方法,在模具钢基体上沉积TiN类薄膜。采用XRD、OM、SEM、EDS等手段分析薄膜的组织和相结构。结果表明,当激光功率为600W,扫描速度为2mm/s,通过H2、N2和TiCl4之间的化学反应,在模具钢表面获得了均匀致密的枝晶组织,其显微硬度最高可达2500HV。     

模具钢表面连续激光沉积TiN类薄膜的研究

利用波长为10．6mm的CO2连续激光诱导化学气相沉积的方法，在模具钢基体上沉积TiN类薄膜。采用XRD、OM、SEM、EDS等手段分析薄膜的组织和相结构。结果表明，当激光功率为600W，扫描速度为2mlrffs。通过H2、N2和TiCl4之间的化学反应，在模具钢表面获得了均匀致密的枝晶组织，其显微硬度最高可达2500HV。     

激光沉积修复ZL114A铝合金的组织及力学性能

采用6 k W光纤激光器对预制槽损伤的ZL114A铸造铝合金进行激光沉积修复实验研究,分析了热处理前后激光修复区的组织形貌及分布规律,并对试样的显微硬度和室温拉伸性能进行了测试。结果表明,修复区与基材形成良好的冶金结合,沉积区底部为近似平行于熔合线法线外延生长的柱状树枝晶,一次枝晶间距约15.7μm,二次枝晶间距约5.2μm,共晶组织呈分叉棒状或块状连续分布于枝晶间隙,在沉积层顶层顶部出现α-Al柱状枝晶转变为等轴枝晶现象。热处理后修复区柱状枝晶的二次枝晶臂因高温原子扩散作用,连成一片,且共晶Si相粒状化明显,粒径约4.93μm,部分颗粒均匀分布于一次枝晶臂的两侧。热处理后修复区硬度较沉积态平均提高约1.6倍,且修复试样的室温拉伸力学性能优于铸造基材。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.