回火工艺对钒氮超低碳贝氏体钢组织性能的影响

为了探索V-N微合金化在低碳贝氏体钢中的应用,利用扫描电镜(SEM)、透射电镜(TEM)、能谱仪(EDS)等实验方法,研究了不同回火温度对轧后保温与直接淬火两种工艺生产的钒氮超低碳贝氏体钢组织性能的影响.结果表明:随着回火温度的升高,屈服强度先升高后降低,直接淬火后600℃回火,材料的屈服强度为805 MPa,较轧态提高200 MPa,而直接淬火回火比轧后保温回火强度高65 MPa;回火后伸长率始终高于轧态.600℃回火时贝氏体基体上存在大量纳米级V(C,N)析出颗粒,对屈服强度的提高起了决定性作用;直接淬火钢回火后组织稳定性更高,析出物更加细小弥散.     

回火温度对690 MPa级工程机械用钢组织与性能的影响

设计了一种低碳Fe-Mn-Nb-Cu-B系屈服强度690 MPa级工程机械结构用钢,利用扫描电镜(SEM)和透射电镜(TEM)等仪器研究了不同回火温度对实验钢的组织和性能的影响.结果表明:回火温度对屈服强度和抗拉强度均有较大影响,都呈现出先降低再升高再降低的规律.600℃回火时的综合力学性能较好,屈服强度比未回火时增加了145 MPa；并且屈强比和硬度随回火温度的变化趋势同抗拉强度和屈服强度的变化规律是相同的.分析认为:回火前后力学性能的变化的主要原因是与回火后有更多弥散的尺寸在20 nm以下的新的细小(Nb,Ti) (N,C)粒子析出以及发生位错的回复和M-A岛的分解有关.     

回火工艺对超低碳微合金钢组织和性能的影响

研究了超低碳微合金钢880 ℃×1 h水淬、不同温度及时间回火后的显微组织及力学性能,结果表明：试验钢经淬火后的显微组织是由粒状贝氏体、板条状贝氏体和残留奥氏体所组成,屈服强度799 MPa,抗拉强度986 MPa,伸长率14.5％,屈强比0.81。随回火温度的升高,屈服强度和抗拉强度增大,并于300 ℃时达最大值,分别为949 MPa和1053 MPa,此时显微组织中开始有析出物产生,随着回火温度继续升高,析出物开始聚集并长大,屈服强度和抗拉强度逐渐降低,屈强比增加,在450℃处达到最大值后开始下降。试验钢的伸长率与回火温度的变化未发现有明显规律。适当延长于380 ℃回火的保温时间后,试验钢的显微组织类型无明显变化,但析出物有聚集长大现象,强度稍有降低,塑性略有增加。     

低碳贝氏体高强钢的析出行为及强化机理研究

制备了低碳贝氏体高强钢,观察了其第二相粒子的析出行为,并对该钢的综合强化机理进行了研究。结果表明,所制备的钢屈服强度达610 MPa、抗拉强度达720 MPa、伸长率为20%,低温韧性良好。此次制备的钢析出粒子有Nb(C,N)、Ti(C,N)、Ti C、Nb C等,析出粒子尺寸均较小,以粒径在50 nm以下的析出粒子最多。细晶强化对低碳贝氏体高强钢的屈服强度贡献值占比为36%;析出强化对屈服强度的贡献值占比为25%;相变强化对屈服强度的贡献值占比约为15%;固溶强化及其他强化方式对屈服强度的贡献值约占比为24%。     

回火温度对TMCP高强钢组织和性能的影响

采用力学性能测试、光学显微镜、透射电镜等方法,研究了回火温度对TMCP高强钢组织和性能的影响。结果表明,经400～650 ℃回火后,钢板强度、冲击吸收能量和屈强比的变化规律明显不同。600 ℃回火时,屈服强度和抗拉强度达到最大值,冲击吸收能量则为最小值,且屈强比随着回火温度的升高而增加。回火后钢板组织以贝氏体为主,析出相为Nb、Ti复合析出,600 ℃时析出少量ε-Cu相,且随着回火温度升高,贝氏体板条逐渐合并,板条宽度增加,Nb、Ti复合析出相数量也随之增加。     

热处理工艺对空气硬化钢S800AH组织及性能的影响

利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、室温拉伸检测等方法研究了热处理工艺对空气硬化钢S800AH显微组织和力学性能的影响。结果表明:空气硬化钢在空冷状态下即获得了大量的马氏体和粒状贝氏体;随热处理温度的升高,空气硬化钢的奥氏体化程度增加,强度先升高后略有下降,屈服强度、抗拉强度在900℃时达到最大,分别为781 MPa和1007 MPa。空气硬化钢具有较高的抗回火性能,当回火温度在500℃以下时,屈服强度和抗拉强度分别仍高于700 MPa和800 MPa。回火过程中细小弥散的析出物抑制了回复与再结晶,同时具有析出强化作用,使得钢具有优良的综合力学性。     

模拟焊后热处理对800 MPa级水电用钢组织和性能的影响

对800 MPa水电用钢进行了模拟焊后热处理,研究了焊后热处理对试验钢组织和性能的影响。结果表明,试验钢经模拟焊后热处理后,组织以贝氏体为主,但较回火态,粒状贝氏体等平衡态组织增多;在焊后热处理过程中,回火过程中析出的析出物未发生明显长大,且有部分较细小的析出物均匀、弥散地在基体上析出。经模拟焊后热处理后,钢板屈服强度和抗拉强度均有所下降,其中,屈服强度下降30~100 MPa,抗拉强度下降20~80 MPa;伸长率均有不同程度的上升,上升幅度在0.5%~2%范围内;模拟焊后热处理并未对试验钢的冲击性能产生明显的影响,试验钢模拟焊后热处理前后韧脆转变温度均在－45~ －50 ℃之间     

热处理温度对纳米析出强化钢组织性能的影响

开展了一系列热处理(500~750℃保温30 min后空冷)实验,分析了热处理温度对新型纳米析出强化钢组织性能的影响。结果表明:未热处理钢板的屈服强度和抗拉强度分别为510 MPa和620 MPa,显微组织为铁素体+珠光体;热处理温度在500~660℃之间时,屈服强度上升幅度在20~45 MPa之间;而热处理温度在700~750℃之间时,由于形成典型双相钢组织(铁素体+M/A岛),屈服强度仅为350 MPa。热处理温度在500~660℃之间时发生了(Nb,Ti)C的二次析出,且原有的析出物具有很好的热稳定性,宏观上表现为实验钢屈服强度提高。     

热处理对SiMn3型贝氏体高强钢组织和性能的影响

利用光学金相、透射电镜（TEM）、扫描电镜（SEM）观察,以及拉伸、硬度、冲击等试验方法,研究了热处理对复合微合金化低碳SiMn3型贝氏体高强钢的组织和力学性能的影响,并对其组织与性能关系进行了讨论.结果表明,该钢在空冷条件下,可获得均一的粒状贝氏体组织,并具有良好的强度与韧性（σ0.2=820 MPa、σb=1118 MPa、αKU=87 J/cm^2）;空冷后经200～300 ℃回火,在贝氏体铁素体（BF）基体上析出了弥散细小的ε碳化物,屈服强度、韧性提高（σ0.2=824～835 MPa、σb=1019～1085 MPa、αKU=136～140 J/cm^2）;在400 ℃以上回火,粒状贝氏体组织开始逐渐分解,BF基体上析出椭球状碳化物,并使强度、韧性降低;500～600 ℃回火,产生回火脆性（σ0.2=787～790 MPa、σb=967～1002 MPa、αKU=72～75 J/cm^2）.空冷后低温回火使该钢获得最佳强韧性组合.     

温度参数对Ti/Ti-Mo微合金钢力学性能及强化机制的影响

对Ti、Ti-Mo微合金钢进行了热轧及离线回火实验,研究了终轧温度、终冷温度及回火温度对实验钢力学性能的影响,并定量分析了相应的强化机制。结果表明,当终轧温度较高时,Ti、Ti-Mo微合金钢的热轧态力学性能较优,经过回火处理后,对应的屈服强度升高,分别达到了715 MPa和710 MPa。回火工艺处理后,Ti、Ti-Mo微合金钢的最大屈服强度增量分别为29 MPa和161 MPa,最大抗拉强度增量分别为7 MPa和88 MPa。实验钢铁素体基体上均存在相间析出与弥散析出,其中弥散析出所占比例较大,在不同工艺下Ti、Ti-Mo微合金钢中析出强化量占屈服强度的比值分别为20%～51%和26%～48%,对应最大析出强化量分别为364 MPa和342 MPa。     

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.