热处理对Ni-P-金刚石化学复合镀层组织结构的影响

研究了热处理对Ni—P—D(金刚石)复合镀层的组织结构的影响。结果表明，复合镀层镀态时为非晶 微晶结构；镀层在300℃加热后开始晶化，晶化后形成晶相Ni和Ni3P，并以Ni3P相为主相；随着热处理温度升高，晶化相不断析出并长大，至500℃晶化基本完成。晶化过程中Ni相的相对含量逐渐增加，最后形成的镀层晶化组织以Ni相为主相。     

Ni-P-金刚石复合镀层的等温晶化动力学研究

采用金刚石作为复合粒子制备了Ni-P-金刚石复合镀层,通过引入晶化方式指数的概念,研究了Ni-P镀层和Ni-P-金刚石复合镀层的等温晶化过程的形核和长大动力学。结果表明,在相同温度下,Ni-P-金刚石复合镀层开始晶化所需时间比Ni-P镀层的少,但其晶化过程进行较为缓慢,完成晶化所需时间较长。说明金刚石的存在有利于晶化过程的开始,但对晶化的进行过程又有阻碍作用。Ni-P-金刚石复合镀层与Ni-P镀层两者的晶化机制是一样的,Ni-P-金刚石复合镀层的晶化方式指数为2．87,Ni-P镀层晶化方式指数为2．91。     

热处理对铝基Ni-P-纳米WC化学复合镀层组织及性能影响

采用化学镀技术在A356合金基体上制备了Ni-P-纳米WC化学复合镀层,并选用真空热处理的方式,对制备的Ni-P-纳米WC纳米复合镀层分别在200、300、400和500℃下进行镀后处理,与镀态下镀层性能进行对比,研究不同热处理温度对Ni-P-纳米WC复合镀层形貌、成分、物相、硬度和耐腐蚀性的影响。结果表明:试验制备的Ni-P-纳米WC复合镀层成分均匀、组织致密,镀层结构呈现非晶态;镀态下,复合镀层硬度达到917.8 HV0.1,约为基体的6倍;在3.5%NaCl溶液中的极化曲线结果显示,复合镀层自腐蚀电流密度比A356合金提高了2个数量级,起到较好的耐腐蚀效果。热处理后镀层发生晶态转变,且随热处理温度的升高,镀层晶化程度提高,400℃以上时镀层完全表现为晶态;热处理态镀层中析出Ni_3P相,镀层硬度随温度的升高呈现先升高后降低的趋势,400℃热处理镀层硬度达到1353.6 HV0.1;与镀态下相比,热处理镀层在3.5%Na Cl溶液中的耐腐蚀性下降,但是仍然表现出较好的耐腐蚀效果。     

Ni-P-纳米SiC化学复合镀层组织与性能研究

为了探讨复合镀层的耐磨性与功能性,制备了Ni-P-纳米SiC化学复合镀层,采用X射线衍射分析了其组织,MM-200型磨损机测试了耐磨性,利用VSM研究了磁学性能.结果表明:热处理使组织发生晶化转变,生成Ni和Ni3P相;纳米复合镀层经500℃×1h热处理达到最佳耐磨值;其磁学性能镀态下比Ni-P镀层略有提高;适当热处理能使复合镀层磁学性能明显提高.     

Ni—P—UFD复合镀层的晶化

采用超细金刚石（UFD）粉末作为复合粒子,制备了Ni-P-UFD复合镀层,研究了复合镀层晶化过程的组织结构转变,并通过差热分析对比研究了Ni-P镀层与Ni-P-UFD复合镀层的晶化温度及晶化激活能。结果表明,非晶态Ni-P-UFD复合镀层热处理时发生晶化,晶化后生成的稳定相为Ni3P和Ni,晶化过程中生成亚稳相Ni5P2,亚稳相最终为地转变成稳定相。在相同的加热速率下,Ni-P-UFD复合镀层晶化的起始温度均低于Ni －P镀层,但峰值温度与Ni－P镀层相当;Ni-P-UFD复合镀层的晶化激活能高于Ni-P镀层,说明UFD加入后非晶镀层的稳定性增加,晶化较难进行。     

化学复合镀Ni-P-金刚石旋转弯曲疲劳性能的研究

为研究Ni-P镀及Ni-P-金刚石化学复合镀对40Cr钢疲劳性能的影响,采用成组对比法进行旋转弯曲疲劳试验,并用SEM对疲劳断口进行对比分析.结果表明:与40Cr基底相比,Ni-P镀件及Ni-P-金刚石镀件的疲劳寿命显著降低,经热处理后寿命进一步降低.镀态时Ni-P-金刚石镀件比Ni-P镀件寿命相对较长,而热处理后Ni-P镀件寿命略长.与基底相比,Ni-P-金刚石镀件主要是由于裂纹扩展区寿命降低,而经热处理后的Ni-P-金刚石镀件主要是裂纹萌生阶段寿命降低.综合试验结果得到:镀件的疲劳寿命主要取决于3个因素,一是镀层自身的脆性;二是镀层与基底间的结合;三是施镀过程中的吸氢.     

金刚石复合镀层的工艺研究

研究了Ni-P-金刚石化学镀液主要成分、pH值、温度以及时问等工艺参数，通过正交实验对金刚石复合镀施镀工艺参数进行了优化，探讨了镀液成分及工艺参数对镀层沉积厚度、镀层中金刚石微粒含量及分布的影响。结果表明，采用合适的工艺条件，可得到金刚石含量较高、均匀分布的复合镀层，Ni-P-金刚石复合化学镀层硬度可达1850HV0．1左右，耐磨性比化学镀Ni-P大大提高。     

化学复合镀镍-磷-金刚石镀速的研究

研究了在化学校镍磷合金镀液中加入金刚石微粒形成镍-磷-金刚石复合镀层的共沉积过程，分析镀液中各成分及操作条件对合金镀层沉积速度的影响，并对镀层的组织和性能进行了测试，结果表明：Ni—P—金刚石复合镀层镀速可达28μm/h，硬度可达HV0.11850左右。     

热处理对金刚石微粉化学镀Ni-P合金层的影响

用化学镀的方法在金刚石微粉表面制备Ni-P合金层,使其表面产生金属化。实验使用的金刚石粒度尺寸为30~40μm,Ni-P合金层使金刚石质量增加30%左右,镀层中磷的质量分数约为7%。用扫描电子显微镜和X射线衍射仪对不同热处理温度下的试样镀层进行了微观形貌和组织结构的研究。结果表明:在一定范围内,随热处理温度的升高,镀层表面变得更加平滑;经400℃热处理后,镀层表面平滑度最高;500℃热处理后,镀层表面粗糙度值变大。镀值态试样经过300℃热处理后,镀层组织开始晶化,析出Ni相和Ni7P3相,镀层结构发生变化。随热处理温度的升高,晶化现象越明显,衍射峰强度越高。经过500℃热处理时,析出了Ni3P相,晶化比较完全,镀层实现了由非晶态向晶态的转变过程。机械搅拌实验证明:经过400℃热处理的金刚石微粉在电镀液中至少可存放48h。     

铸铝表面制备环保型Ni-P-金刚石化学复合镀层

为提高铸铝表面耐磨耐蚀性能,采用化学复合镀技术在其表面制备环保型Ni-P-金刚石复合镀层,研究了温度及搅拌等关键因素对复合量及显微硬度的影响,对镀层耐磨性及耐蚀性进行了研究,并通过EDX能谱仪分析了镀层组成.结果表明:Ni-P-金刚石化学复合镀层可有效提高铸铝表面耐蚀性及耐磨性,且复合镀层耐磨性显著优于Ni-P镀层,但前者耐蚀性不及后者;温度和搅拌均通过影响金刚石微粒在镀件表面的滞留而对微粒进入镀层产生作用.     

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.