热氧化温度对TA2纯钛组织与耐蚀性的影响

对TA2工业纯钛进行不同温度热氧化处理.采用光学显微镜(OM)和扫描电子显微镜(SEM)分析热氧化处理试样截面组织,用EDS和XRD进行微区成分和物相分析;研究不同温度氧化处理试样的表层显微硬度以及浓盐酸中的耐腐蚀性,采用SEM观察试样腐蚀前后表面形貌.结果表明,热氧化后TA2表面形成了金红石型TiO2氧化膜,整个氧化层由金红石型TiO2氧化层、外扩散层和内氧扩散层构成.TiO2氧化膜厚度随热氧化温度升高而增加, 700 ℃以下增速很缓、超过700 ℃快速增厚;热氧化处理表层硬度亦随热氧化温度升高而提高.热氧化TA2试样在36%～38%HCl中耐腐蚀性明显改善,其中700 ℃热氧化处理的耐蚀性最优.     

Ti6Al4V钛合金表面真空渗氧处理

目的在Ti6Al4V钛合金表层制备硬度高、耐磨性好的硬化层。方法结合真空技术,以高纯的O2为介质,在Ti6Al4V钛合金表面制备致密的渗氧硬化层,采用X衍射仪分析渗氧层的相组成,用金相显微镜观察渗氧层和磨痕组织,用显微硬度计测试渗氧层的显微硬度,用MM-U10A端面磨损试验机研究渗氧层的耐磨性。结果渗氧层物相主要由TiO_2、TiO、Ti_3Al及Al_2O_3组成,温度较低时,形成的渗氧层较薄,温度增加,渗氧层厚度迅速增加,硬度及耐磨性也随之增加。温度为760℃时,表面硬度为基体硬度的2.5倍以上,大于750HV,有效硬化层厚度达60μm以上,其磨损失重仅为未渗氧原样的1/4,表面磨痕细密,没有撕裂情况发生,渗氧层保持完整。温度继续增加,氧化物开始聚集长大,渗氧层组织开始变得疏松,硬度及耐磨性开始下降。结论 Ti6Al4V钛合金表面真空渗氧处理可显著提高其表面硬度,耐磨性改善明显。     

Ti60高温钛合金氧化行为研究

研究Ti60高温钛合金在600～750 ℃范围内的氧化行为.氧化增重试验及XRD、SEM分析结果表明,Ti60合金在600～750 ℃范围内氧化0～100 h条件下,由Wagner的氧化经验公式计算得氧化指数n在1～2之间,氧化激活能为256 kJ/mol,氧化符合线性-抛物线混合规律.在600 ℃氧化100 h及750 ℃氧化10 h,氧化产物为TiO2,经750 ℃、100 h长时间氧化后,表面有少量Al2O3生成,氧化物优先沿原始β晶界形核.氧除了会在试样表面形成氧化层外,还会向基体中扩散形成脆性富氧层,从而影响合金力学性能.随着氧化温度的升高和时间的延长,富氧层厚度增厚.     

TC4钛合金真空渗氮组织与性能

对TC4钛合金进行真空渗氮处理,通过X射线衍射(XRD)、扫描电镜(SEM)、显微硬度计及耐磨试验机分析了渗氮层的组织与性能。结果表明,TC4钛合金经真空气体渗氮处理后,形成了由TiN、Ti2AlN和钛铝金属间化合物Ti3Al组成的复合改性层,氮化层组织均匀致密,形成了较宽的氮扩散区,表面硬度为1100~1200 HV,有效硬化层深度为50~60μm,硬度梯度平缓,脆性低,耐磨性得了极大的改善。     

TC4钛合金热氧化层微米压痕/划痕试验研究

采用微米压痕实验测试了氧化层的硬度、弹性模量,研究了热氧化工艺对TC4钛合金表面热氧化层力学性能的影响;通过微米划痕实验考察了氧化层的临界荷载以及划擦行为.结果表明:热氧化处理后TCA表面生成由金红石TiO2和少量Al2O3所组成的氧化层,钛合金表面硬度和弹性模量显著增加,弹性模量与硬度的比值降低,表明热氧化工艺可改善钛合金的耐磨性.长时间的高温氧化可以增加氧化层的厚度,但在划擦过程中氧化层发生两次脱落,表明氧化层由外表层和次外层组成,外层结合力差,易发生一次脆性剥落.内层与基体的结合强度较高,但在较大载荷作用下会产生微裂纹,导致氧化层的二次剥落.     

少无氧扩散处理对热浸镀铝奥氏体钢氧化开裂影响的实验研究

对扩散热处理后的热浸镀铝1Cr18Ni9Ti奥氏体不锈钢进行1000℃高温氧化试验,发现直接扩散处理试样在氧化120 h后表面出现明显开裂,而少无氧扩散处理试样经500 h氧化后表面完好。通过金相显微镜、扫描电镜和能谱仪的观察及分析表明,由于扩散前期在外扩散层形成的Fe-Al合金(脆性相Fe2Al5和条状FeAl2)为氧提供了扩散通道,导致直接扩散试样的合金层内产生了内氧化空洞,在高温氧化阶段,内氧化占据主导地位,使镀层表面开裂。少无氧扩散能够防止氧进入合金层内部,而且随着扩散的进行,合金层的相组成及形态变化也对氧向内扩散起阻碍作用。少无氧扩散试样的高温氧化由外向内进行,延缓了合金层的开裂和脱落。     

Effect of Diffused Heat Treatment with Little or No Oxygen on High Temperature Oxidation Cracks of Hot-dip Aluminizing Austenitic Stainless Steel

对扩散热处理后的热浸镀铝1Crl8Ni9Ti奥氏体不锈钢进行1000℃高温氧化试验,发现直接扩散处理试样在氧化120h后表面出现明显开裂,而少无氧扩散处理试样经500h氧化后表面完好.通过金相显微镜、扫描电镜和能谱仪的观察及分析表明,由于扩散前期在外扩散层形成的Fe-Al合金(脆性相Fe2Al5和条状FeAl2)为氧提供了扩散通道,导致直接扩散试样的合金层内产生了内氧化空洞,在高温氧化阶段,内氧化占据主导地位,使镀层表面开裂.少无氧扩散能够防止氧进入合金层内部,而且随着扩散的进行,合金层的相组成及形态变化电对氧向内扩散起阻碍作用.少无氧扩散试样的高温氧化由外向内进行,延缓了合金层的开裂和脱落.     

氮碳氧复合处理(QPQ)对MPS700A钢组织与性能的影响

采用氮碳氧复合处理(QPQ)技术对耐蚀耐热不锈钢MPS700A钢进行表面改性,分别进行(450～500) ℃×5 h和(550～570) ℃×3 h盐浴氮碳共渗试验,氧化处理工艺均为400 ℃×30 min。对QPQ处理后试样渗层的表面形貌、表面硬度、脆性及其耐磨性进行了分析。结果表明:渗层主要由氧化膜层、疏松层、化合物层和扩散层构成,QPQ处理后试样的硬度明显提高,相对低温段490 ℃盐浴氮碳共渗试样的硬度最高,相对高温段550 ℃处理的试样硬度最高,分别为1295、1344 HV0.1,分别是基体硬度的3.75和3.90倍。QPQ处理试样的渗层组织细小,均匀致密,脆性低,耐磨性好,比祼钢具有较好的高温摩擦磨损性能,尤其在500 ℃以上性能更加优异。且与550 ℃盐浴氮碳共渗QPQ试样相比,490 ℃盐浴氮碳共渗QPQ试样具有更低的脆性,更好的高温摩擦磨损性能。     

预氧化处理对钛合金抗高温氧化行为的影响

研究了预氧化处理对Ti06Al-4V合金在600℃空气中高温氧化行为的影响。利用XRD和SEM对氧化层表面形貌、相组成及氧化层断面组织结构进行分析。结果表明：预氧化处理的钛合金表面形成了较为致密的Al2O3和TiO2氧化膜，在氧化试验过程中，不仅改变合金的氧化机制，合金由高温氧化时氧向内部扩散为主转变为钛原子向外扩散为主，而且明显降低了合金的氧化速率，提高了氧化膜的粘附性和抗剥落能力。     

双相不锈钢低温离子硬化处理工艺

采用低温离子渗氮和氮碳共渗对双相不锈钢进行试验,利用显微硬度计、光学显微镜、X射线衍射仪分别研究了表面硬度、硬度梯度、表面脆性、硬化层横截面显微组织、硬化层结构。结果表明,低温离子渗氮和氮碳共渗后硬化层的性能(表面硬度、硬化层厚度、显微组织、物相结构)变化规律大致相同:随着处理温度的提高或者时间的延长,表面硬度和硬化层厚度不断提高,但最后趋于平缓;表面脆性略有增加。     

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.     

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.     

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.