TA15钛合金大型锻坯工艺及组织与性能研究

研究了TA15钛合金大型锻坯的工艺、组织与性能。结果表明:在940～970℃加热锻造,TA15钛合金组织对加热温度敏感,随着温度的提高,初生α相含量减小,合金的室温和500℃高温强度均降低,塑性几乎保持不变,冲击韧性小幅提升;在760～840℃退火,随着温度的提升,细针状α相弥散析出,强度提升,塑性和冲击韧性变化小。锻坯锻造加热温度应控制在950℃,退火温度选择840℃。     

GH4033合金粗轧加热过程晶粒长大模型

以GH4033合金锻坯为研究对象,在850~1200℃的温度范围内,借助激光共聚焦高温显微镜研究了加热温度和保温时间对GH4033合金锻坯晶粒尺寸变化的影响,推导并验证了具有普适意义的适合GH4033合金锻坯粗轧加热过程的晶粒长大模型。研究结果表明:随加热时间的延长,在850~1050℃加热时,晶粒尺寸变化不显著,且呈线性长大;1100~1200℃加热时,晶粒尺寸呈抛物线性长大,加热时间低于30 min时,晶粒尺寸随温度升高急剧长大,30 min后晶粒尺寸变化不显著,45 min后出现混晶现象。用于热加工的锻坯,加热温度低于1100℃时,有利于细化晶粒;加热温度高于1100℃时,保证坯料断面均温时间处于30~45 min可有效避免混晶。     

GH141合金晶界上M23C6的连续沉淀对持久性能的影响

研究了GH141合金晶界M23C6连续沉淀对合金持久寿命的影响。实验发现,晶界M23C6连续沉淀对持久寿命的降低,可能与热加工温度过高,或变形量较小有关。     

700℃先进超超临界锅炉过热器管用新型镍基高温合金GH750的组织和性能研究

GH750是一种我国自主研发的、可以应用于700℃先进超超临界锅炉过热器/再热器管的新型镍基高温合金。研究新型镍基高温合金GH750的组织和性能。研究结果表明:GH750合金的组织由奥氏体基体和强化相γ′,以及微量的晶内和晶界MC、M23C6组成;力学性能优异,室温和高温强度高、塑性好;高温持久性能突出,760℃/10~5 h的持久强度超过100 MPa;在750~850℃高温长期时效后组织稳定性好,无有害相析出;长期时效至10 000 h时,室温拉伸性能变化小,冲击韧性短期下降后趋于稳定。     

GH738高温合金热加工行为

采用Gleeble-1500热模拟机对GH738镍基高温合金进行高温热压缩变形实验,分析该合金在变形温度1000~1160℃、应变速率0.01~10s-1、工程变形量15%~70%条件下流变应力的变化规律。确定GH738合金热变形方程,建立热加工图(Processing map),并通过组织观察对热加工图进行解释。GH738合金热变形激活能Q为499kJ/mol;热加工图随不同变形量而变化,在应变速率较低,温度较高的状态下,能量耗散效率较高。综合应变量为0.2,0.4,0.6和0.8应变量下的热加工图,确立了该合金最佳热加工"安全通道",为GH738高温合金热加工工艺优化提供理论依据。     

旋锻Mo-Ti-Zr合金棒材的退火行为

采用冷等静压、高温烧结和直接高温旋锻的方法制备Mo-Ti-Zr合金棒材,研究不同退火温度对合金力学性能与显微组织的影响以及对断面收缩率为30%的旋锻Mo-Ti-Zr合金棒材的退火行为。结果表明:当退火温度低于1000℃时,随着退火温度的升高,Mo-Ti-Zr合金硬度未急剧下降,抗拉强度和伸长率逐渐提高;经900℃退火后,合金抗拉强度达到669MPa,伸长率达到3.1%,获得良好的综合力学性能;当退火温度在800～1000℃范围内时,Mo-Ti-Zr合金晶粒发生再结晶细化;旋锻态Mo-Ti-Zr合金的断口主要为穿晶解理断裂,随着退火温度的提高,出现较多细晶粒的穿晶断裂和沿晶断裂。     

GH141高温合金矩形环件热处理工艺研究

GH141高温合金矩形环件的热处理一般经过退火、固溶和时效3个阶段,每个阶段都会对环件的微观组织产生重要影响。由于退火和固溶处理的温度较高,对环件的晶粒尺寸、碳化物含量等组织影响更为显著。因此,本文主要针对GH141高温合金矩形环件的退火和固溶热处理进行了试验研究。结果表明,经过1080℃退火处理,径轴双向辗轧成形的环件边角处的晶粒会发生一定程度的长大,而其它区域的晶粒尺寸基本不发生变化,退火时间对晶粒尺寸影响较小。1120℃固溶处理后,GH141合金环件晶粒尺寸明显增大。但是在本试验条件下,随着固溶时间的增加,晶粒尺寸基本不发生变化。     

变形及热处理工艺对GH4169合金超塑性的影响

针对GH4169合金进行了不同变形工艺的超塑性拉伸和热处理试验,研究变形及热处理对合金塑性的影响。结果表明,锻态合金分别经过890℃×10h+950℃×1h和890℃×10h+950℃×3h的退火热处理后,发现延长第二次退火时间可有效细化晶粒;利用最大应变速率敏感指数法(最大m值法)进行不同温度的超塑性拉伸试验,在950℃时合金的伸长率最佳;延长第二次退火时间可显著提高试样的伸长率;采用基于最大m值法的应变诱发超塑性法对合金进行超塑性拉伸试验,可知预变形拉伸后,保温20min后其伸长率最佳;在890℃×10h+950℃×3h热处理后合金伸长率达566%,较单纯m值法拉伸后合金的伸长率显著提高。     

GH4698高温合金变形中的流变行为及显微组织

在热模拟试验机上进行了高温压缩试验,研究了GH4698高温合金在不同变形温度(950~1200℃)和应变速率(0. 01~10 s^-1)条件下的流变行为,建立了基于流变曲线的本构方程及以动态材料模型为基础的热加工图。借助扫描电镜和背散射电子衍射技术(EBSD)对变形后试样进行组织分析。结果表明:GH4698高温合金流变应力随着变形温度的降低和应变速率的加快而逐渐增加。在变形温度为1000~1200℃、应变速率为0. 01~0. 05 s^-1的热变形条件下,GH4698高温合金具有较佳的热加工行为。在高、低功率耗散率区域中,随着功率耗散率值的增加,动态再结晶百分数均会增加,再结晶平均晶粒尺寸增大,大角度晶界分数增加。     

锻造工艺对GH901高温合金涡轮轴锻件磨损性能的影响

采用不同的始锻温度、终锻温度和锻压速度对GH901高温合金涡轮轴毛坯进行了锻造,并分别进行了25℃室温和600℃高温环境下的耐磨损性能测试与分析。结果表明:在试验条件下,随始锻温度从1060℃升高至1140℃,终锻温度从860℃升高至940℃,或锻压速度从6 mm/s增加至12 mm/s,锻件的室温和高温磨损体积均先减小后增大,耐磨损性能先提高后下降。高温合金涡轮轴锻件始锻温度优选为1120℃,终锻温度优选为920℃,锻压速度为10 mm/s。     

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.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.