高铬白口铸铁耐磨性和显微组织的关系

研究了高铬白口铸铁亚临界热处理后耐磨性和显微组织的关系。结果表明，高铬铸铁在亚临界热处理过程中C和Cr以M23C6型二次碳化物的形式析出，导致奥氏体Ms点升高，使其在冷却时发生马氏体转变。马氏体的高硬度改善了合金耐磨性。合金耐磨性和合金组织中残留奥氏体含量具有相互对应关系，本试验中此含量为10％左右。当残留奥氏体含量低于10％时，由于（Fe，Cr）23C6发生向M3C型碳化物的原位转变，相应的组织转变为珠光体，导致耐磨性急剧下降。     

Mo、Cu对高铬铸铁凝固组织和亚临界热处理硬化行为的影响

研究了Mo和Cu对高铬铸铁凝固组织和亚临界热处理硬化行为的影响。研究表明，添加Mo和Cu可以使高铬铸铁的凝固组织获得更多的残留奥氏体。含有Mo和Cu的高铬铸铁在亚临界热处理过程中有明显的二次硬化现象。由于Mo是强碳化物形成元素与碳原子之间有强的相互吸引作用，阻碍碳原子在凝固冷却时碳从奥氏体向液相扩散，使共晶奥氏体的碳含量较高，导致奥氏体的Ms点降低，使得铸态组织获得更多的残留奥氏体。固溶于奥氏体中的Cu对奥氏体中碳在亚临界热处理过程中的析出具有很强的阻碍作用，所以与没有添加Mo和Cu的高铬铸铁比较，添加Mo和Cu的高铬铸铁二次硬化峰的出现需要更高的温度或者更长的保温时间。     

亚临界热处理对不同Cr/C高铬铸铁的组织与相变的影响

研究了不同Cr/C的高铬铸铁经亚临界热处理前后组织与性能的变化规律.结果表明,在亚临界热处理时,Cr/C越高越有利于二次碳化物的析出,越能降低奥氏体的过饱和度,提高M2点转变温度,在空冷时基体中马氏体含量也就越高,材料的力学性能得到提高,进而提高了材料的耐磨性.     

不同热处理对一种高铬铸铁组织的影响

用X射线衍射（XRD）、磁性法和透射电镜（TEM）等方法研究了不同热处理对一种含Mo、Cu高铬铸铁的组织的影响。结果表明：高铬铸铁亚临界处理和去稳处理中,基体会以二次碳化物的形式析出过饱和的碳和合金元素,残余奥氏体发生马氏体转变。在亚临界处理中,处理温度越高,马氏体转变越快;在去稳处理过程中,当温度为1000℃时残余奥氏体量最少,随着处理温度的提高,残余奥氏体反而增多。二次碳化物析出的顺序是首先析出颗粒状的（Fe,Cr）23C6,然后随着保温时间的延长（Fe,Cr）23C6发生原位转变为M3C,基体部分转变为珠光体。     

分级保温热处理对高铬白口铸铁组织和性能的影响

研究了分级保温热处理对高铬白口铸铁组织转变、硬度、冲击韧性及耐磨性的影响。结果表明:高铬白口铸铁分级保温处理中,基体中过饱和的碳和合金元素会以二次碳化物的形式析出,残留奥氏体发生马氏体转变。在1150℃×2 h+890℃×5 h分级保温过程中,随着保温时间的延长有大量二次碳化物析出,首先析出颗粒状的(Cr,Fe)23C6,然后基体和(Cr,Fe)23C6发生原位转变生成片状的(Cr,V)2C和长条状的(Cr,Fe)7C3,有效地提高了合金的硬度、冲击韧性及抗磨损能力。     

深冷处理对Cr13Mn3MoV2硬度和耐磨性能的影响

研究了高铬铸铁Cr13Mn3MoV2经亚临界与深冷处理后的组织、硬度和耐磨性.结果表明,高铬铸铁的显微组织主要是由奥氏体、马氏体和(Cr,Fe)7C3共晶碳化物组成.高铬铸铁经深冷处理后的硬度明显高于空冷,相比铸态,随着亚临界处理温度从400℃到650℃,其经历了从低于铸态硬度到硬度增大并超过铸态,并且出现二次硬化再到硬度又降低的过程,这主要是在热处理过程中马氏体的回火及残余奥氏体转化为马氏体的结果.在520℃和600℃进行亚临界处理耐磨性最好,而在540℃,其耐磨性能最差,而且硬度与耐磨性没有完全的对应关系.     

含V多元合金白口铸铁的试验研究与应用

加V可以细化高铬铸铁的奥氏体晶粒,形成M7C3型碳化物和硬度很高、以V为主的MC型碳化物.由于V促进碳化物析出,有可能在亚临界条件下获得马氏体组织,减少残余奥氏体量,因而可以使铸件不经高温热处理获得高耐磨性.用含V白口铸铁(质量分数为C 3.0%,Si 1.1%,Mn 1.1%,Cr 10.2%,V 8.9%,Mo 0.4%,Ni 0.5%,Cu 1.0%)浇注LPC-Ⅲ型破碎机锤头,经560℃、3 h亚临界热处理后进行使用试验,结果表明,其寿命为高Cr铸铁锤头的3倍.     

合金化对高铬铸铁相析出的影响

添加多元微量合金元素V、Ti、Nb和Mo到2.8C-31Cr合金中制备多元铬系合金,从合金热力学析出角度,通过计算分析Ti、V、Nb在多元体系中的存在方式,探讨添加的合金元素对高铬铸铁凝固组织中碳化物析出的影响。结果表明,Ti和Nb在高铬铸铁凝固过程中主要形成Ti C和Nb C,V主要存在于合金化合物VCr2C2和VCr Fe8中。先析出的Ti C和Nb C能充当碳化物异质形核基底,增加形核率使组织细化。但添加过量的合金元素却削弱了对碳化物的细化作用。     

碳量变化对高铬铸铁初生奥氏体稳定性的影响

通过改变高铬铸铁(Cr15)的含碳量,研究了高铬铸铁凝固过程中初生奥氏体中C、Cr量变化对初生奥氏体稳定性的影响。结果表明,较快的冷速条件下自液体中析出的初生奥氏体固溶的C、Cr量远高于平衡条件;在本试验冷却条件下,随着碳含量的增加,初生奥氏体中固溶的C量增加、Cr量减少,这使C原子的扩散增强,并且奥氏体过饱和程度增大,二次碳化物析出趋势增强;当二次碳化物未析出时,碳量的增加使奥氏体稳定性增加,而一旦二次碳化物析出,碳量的增加使奥氏体的稳定性变差;碳量2.63%为奥氏体能否析出二次碳化物的临界值。     

锰对高铬铸铁凝固组织和亚临界硬化行为的影响

采用电子探针、X射线衍射、磁性法和硬度测量等方法研究了两种不同含锰量高铬铸铁的凝固组织和在亚临界处理过程中的硬化行为。结果表明，含锰量分别为2．68％和1．98％的两种高铬铸铁的凝固组织都由奥氏体、马氏体和M7C3型碳化物组成。二者的共晶碳化物数量相当，前者和后者的奥氏体和马氏体含量分别为66．2％、13％和11．8％、68．2％。在亚临界处理中，高铬铸铁出现二次硬化，且前者的二次硬化更明显。这一现象归因于高铬铸铁在亚临界处理过程中所发生的马氏体相变。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

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。     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

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.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.