一种新型镍基粉末高温合金不同状态热变形行为研究

利用扫描电子显微镜、金相显微镜、热压缩试验机、电子背散射衍射仪等研究了一种新型镍基粉末高温合金(WZ-A3)在1150℃热等静压态、热等静压+1150℃热挤压态、热等静压+1130℃热挤压态等三种不同状态下显微组织、热变形行为和组织演变。结果表明：WZ-A3材料1150℃热等静压态样品存在部分粉末原始颗粒边界(Prior Particle Boundary,PPB)和粗大γ′,经1130℃和1150℃挤压后样品PPB碎化消失,为等轴晶状态。三种状态样品在热压缩过程中均表现出加工硬化-再结晶软化现象。峰值应力热变形激活能分别是861kJ/mol、858 kJ/mol和489kJ/mol。变形温度对样品变形组织影响明显,1150℃-0.001/s条件下,热等静压态和热等静压+1130℃热挤压态样品均出现异常晶粒长大。对比三种状态,热等静压+1130℃热挤压态样品变形行为最优。     

FGH97高温合金不同控制模式低周疲劳性能研究

研究了氩气雾化制粉+热等静压+热处理的全尺寸FGH97合金盘件不同位置组织、650℃拉伸性能、应力和应变控制方式低周疲劳性能及其断口形貌，结果表明：盘件不同位置晶粒度、γ′相尺寸形貌相似，650℃抗拉强度在1325-1340MPa间，650℃屈服强度1010-1025MPa。应力控制低周疲劳寿命（Nf）均值约200000周次，Weibull分布尺度因子η=215194，尺寸＜80μm的夹杂物对Nf影响不明显。应变控制Nf＜20000周次时，η=14622，Nf＞20000周次时，η=44342；夹杂物面积变化引起Nf值Weibull分布特征值β不同。两种控制方式下，疲劳断口裂纹源都主要由夹杂物引起，断口形貌无明显差异。应变控制对夹杂物更敏感。     

热等静压处理温度对一种高性能粉末高温合金组织和性能的影响

采用光学显微镜、扫描电镜和拉伸试验等研究了不同温度热等静压处理(HIP)对一种高性能粉末高温合金显微组织和力学性能的影响。结果表明:在γ′相溶解温度以下进行热等静压处理,合金中存在较多的原始粉末颗粒边界(PPB)组织,并且含有大量的残留枝晶,热处理后PPB不能完全消除,以至于影响合金的室温和高温塑性;在γ′相溶解温度以上进行热等静压处理,基本消除了PPB组织,残留枝晶含量较少,热处理后得到完全再结晶组织,不含有PPB组织,同时晶粒并未快速长大。     

粉末粒度对一种新型镍基粉末高温合金热变形行为的影响

用带有能谱仪和电子背散射衍射仪（Electron Back-Scatter Diffractometer,EBSD）的扫描电子显微镜（Scanning Electron Microscope,SEM）、金相显微镜（Optical Microscope,OM）、热模拟试验机等对比研究了不同粉末粒度制备的一种新型镍基粉末高温合金（WZ-A3）在不同热压缩变形条件下的变形行为和组织差异性,结果表明：相比细粉制备的HIP-01而言,粗粉枝晶组织明显,成分偏析严重,其制备的HIP-02样品中残余粗大γ′较多。低温（1050℃、1080℃）高应变速率（1/s、0.1/s）时,HIP-01样品峰值应力值高于HIP-02。热压缩后HIP-01样品边缘开裂情况较HIP-02严重,HIP-01样品保留了大部分原始热等静压组织,裂纹优先在粉末原始颗粒边界（Prior Particle Boundary,PPB）处产生,HIP-02边缘出现了部分再结晶组织。1080℃-0.001/s时,HIP-02样品峰值应力较HIP-01样品低约30MPa,HIP-02样品热压缩过程再结晶现象明显,再结晶晶粒均匀,HIP-01样品出现项链晶组织,再结晶不充分。粗大γ′有利于促进1050℃和1080℃时HIP-02样品的再结晶。高温（1150℃）低应变速率（0.001/s、0.01/s）时,γ′全部溶解进基体γ中,两者热变形行为接近,样品均未出现开裂,组织全部发生完全再结晶,1150℃-0.001/s均出现异常长大晶粒。     

FGH4113A合金的双性能热处理组织与力学性能研究

利用扫描电子显微镜（Scanning Electron Microscope,SEM）、光学显微镜（Optical Microscope,OM）、拉伸、蠕变、疲劳试验机等研究了一种新型镍基粉末高温合金FGH4113A（WZ-A3）在两种热处理状态下的显微组织和力学性能,为双性能热处理研究提供组织与力学性能依据。结果表明：FGH4113A合金在双性能热处理中,过固溶与亚固溶态组织与力学性能具有明显的双模特性;室温下,亚固溶态相比过固溶态屈服强度高10.6%,800℃下,过固溶态相比亚固溶态屈服强度高11.7%;与同样是亚固溶或过固溶的其它合金相比,FGH4113A的拉伸强度优于ME3合金,与LSHR合金相当;FGH4113A合金在750℃/450MPa的蠕变变形以位错滑移机制主导,弥散分布的小尺寸硼化物有助于蠕变性能的提高,其蠕变性能全面超过ME3合金,与LSHR合金相当;过固溶态的粗晶组织在裂纹扩展中具有更长的滑移带,在循环载荷中具有较低的累积损伤,抗裂纹扩展能力优于亚固溶态;过固溶态的裂纹扩展断口呈现穿晶断裂特征,亚固溶态由于细晶粒边界的一次γˊ的存在降低了晶界的抗裂纹扩展能力,断口较粗糙,呈现沿晶-穿晶混合断裂特征。     

一种新型第三代镍基粉末高温合金的微观组织及其力学性能研究

本工作研究了一种自主研发的第三代粉末高温合金WZ-A3不同工艺状态的显微组织特征以及热处理后合金的高温拉伸、蠕变以及疲劳性能。该合金采用热等静压(HIP)+热挤压(HEX)+锻造(HF)+热处理(HT)工艺加以制备。结果表明:HIP态合金晶粒度等级为ASTM8~9级,晶界存在粗大γ＇相,晶内存在相对细小的γ＇相;经挤压+锻造后,合金晶粒度等级可达ASTM13~14级,晶内γ＇相细化,但晶界处的γ＇相数量明显增多;热处理后合金晶界处大块状的γ＇相数量明显减少,晶内γ＇相平均尺寸由HIP态的400nm细化至热处理态的200nm。过固溶+时效热处理后的合金700℃抗拉强度和屈服强度分别达1360MPa和1029MPa,延伸率和断面收缩率分别为23.5%和17%;在800℃/330MPa条件下蠕变量达0.2%时所用时长为229小时;700℃/0~0.8%/0.33Hz条件下的疲劳寿命为24500循环周次。蠕变性能和疲劳性能与LSHR和ME3等三代镍基粉末高温合金相当,但700℃拉伸强度较LSHR合金高近50MPa,延伸率为其3倍,屈服强度稍有降低。     

氩气雾化制粉FGH97高温合金组织和性能研究

利用扫描电子显微镜、金相显微镜等研究了氩气雾化制粉(Argon Atomization,AA )+热等静压(Hot Isothermal Pressing ,HIP)的FGH97合金显微组织、夹杂物、原始颗粒边界（Prior Particle Boundary,PPB）、热诱导孔洞（Thermally induced porosity,TIP）等冶金缺陷,统计分析了室温、650℃、750℃拉伸性能、650℃/980MPa持久性能及650℃低周疲劳寿命。试验结果表明：AA + HIP +热处理制备的FGH97材料晶粒度为ASTM8-9级,未发现连续网状的PPB,存在极少量的TIP。晶内γ′多数为正方形,尺寸约为200nm,晶界γ′为1.5～2 μm的长方形,未见粗大γ′相及粗大碳化物。650℃/980MPa 持久时间均值449 h。650℃低周疲劳寿命最大值258909周次,均值达到190014周次。室温、650℃、750℃拉伸性能、650℃/980MPa持久性能以及650℃低周疲劳寿命均满足FGH97合金技术要求。     

一种新型粉末高温合金的低周疲劳行为与寿命预测模型分析

对一种新型第3代粉末高温合金A3在700℃、应变范围0.6%～1.4%试验条件下的低周疲劳性能进行了研究,分析了材料的循环滞后回线、Massing特性、循环应力应变响应、应变-寿命关系等特性。采用Manson-Coffin模型、拉伸滞回能模型、三参数能量模型对疲劳寿命数据进行拟合预测,结果表明Manson-Coffin模型的寿命预测精度最高,在3倍分散带以内。用扫描电子显微镜对疲劳源区观察,结果表明:低应变时疲劳源数量上呈现单源,高应变时呈多源特征;随应变量增大,疲劳源位置趋向于试样表面,裂纹扩展区面积减小,瞬断区面积增大。疲劳断口典型的3个区域观察结果表明:疲劳源四周存在较多河流状线,其为裂纹扩展方向,裂纹扩展区存在较多二次裂纹,瞬断区出现韧窝与解理断裂特征。A3合金的断裂模式主要为穿晶断裂。     

热等静压法制备细晶γ-TiAl及可成形性研究

采用低温高能球磨法和热等静压技术制备出细晶Ti-45Al-2Cr-2Nb-1B合金,采用XRD、TEM对热等静压烧结后组织形貌进行分析,采用INSTRON 4200型拉伸试验机对热等静压后的材料进行拉伸性能测试.研究表明,在不同条件下烧结,其相组成为γ-TiAl和少量Ti3Al,晶粒尺寸为细晶结构(低于500 nm).对块体材料进行室温和高温拉伸试验,研究表明室温具有很低的塑性,认为粉末间没有很好的结合:850℃高温拉伸试验,强度为60～80 MPa、延伸率为63%～101%,具有很好的塑性,表现出很好的高温可成形性.这表明,可以在800～900℃条件对钛铝烧结块进行二次加工(锻造或轧制)获得致密高强度的细晶钛铝块体或板材;对热等静压制备的TiAl的可成形性进行了讨论.     

热等静压对高温合金薄壁铸件疏松缺陷及性能的影响

研究了热等静压处理(1160℃/130 MPa/4 h)对K4169高温合金微观疏松,室温、高温拉伸和持久性能的影响规律。结果表明:热等静压处理可有效消除薄壁铸件凝固过程形成的内部微观疏松;进一步经过热处理(1095℃均匀化+955℃固溶+720℃时效)后,高温合金室温和高温650℃拉伸性能均明显提高,尤其是屈服强度提高10%以上;此外,经过热等静压处理(650℃/620 MPa)后持久寿命比未经热等静压处理的持久寿命提高了3倍。     

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.