磷元素的非平衡晶界偏聚对A690M海洋环境用钢耐海水腐蚀性能的影响

采用俄歇能谱分析了A690M海洋环境用钢在600℃回火过程中磷元素的晶界偏聚行为,结合极化曲线和腐蚀锈层的微观分析探讨了P元素晶界偏聚对A690M钢耐海水腐蚀性能的影响。研究表明:A690M钢中P元素的晶界偏聚符合空位-溶质原子复合扩散导致的非平衡偏聚机制;P的晶界偏聚含量越高,锈层内部越易形成层状磷疤坑,使板坯耐海水腐蚀性能降低。     

碳含量对含钼钢中磷、钼和碳晶界偏聚的影响

采用俄歇剥层分析测定了经 116 0℃淬火和 40 0～ 6 5 0℃回火的Fe 4Mo 0 1P C钢中磷、钼和碳的晶界偏聚。研究了碳含量对含钼钢中磷、钼和碳晶界偏聚的影响 ,以及碳和磷、碳和钼、磷和钼的交互作用。研究结果表明 ,在含钼钢中提高碳含量可降低在回火脆温度范围内磷的晶界偏聚 ,增加钼的晶界偏聚。碳的晶界偏聚随钢中碳含量的增加而增加。钼和碳、钼和磷具有晶界共偏聚行为 ,而碳和磷却产生相互排斥和 或占位竞争作用     

TEMPER BRITTLENESS OF P-DOPED STEELS 35CrMnSi AND 35CrNi3——Grain Boundary Segregation of P and Effect of La Addition

用Auger电子能谱(AES)研究了含磷450ppm的35CrMnSi和35CrNi3钢回火脆性与杂质元素磷及合金元素Ni,Cr,Mn晶界偏聚的关系。含磷钢的回火脆性主要是由磷在原奥氏体晶界偏聚所致。经1200℃油淬、625℃回火1h水冷的所谓“韧态”,磷已在晶界大量偏聚,钢已明显脆化;经阶梯冷却脆化处理后,晶界磷浓度成倍增加。在阶梯冷却脆化期间,Ni-Cr钢中磷的晶界偏聚速率比Cr-Mn-Si钢大。试验钢的FATT与晶界含磷量成正比;Ni-Cr钢中晶界Ni与磷呈线性关系。试验钢中加入La能够减少相同状态下的晶界磷浓度,从而改善钢的回火脆性。     

含磷Cr-Mn-Si和Ni-Cr钢回火脆性的研究——磷在晶界偏聚及添加La的作用

用Auger电子能谱(AES)研究了含磷450ppm的35CrMnSi和35CrNi3钢回火脆性与杂质元素磷及合金元素Ni,Cr,Mn晶界偏聚的关系。含磷钢的回火脆性主要是由磷在原奥氏体晶界偏聚所致。经1200℃油淬、625℃回火1h水冷的所谓“韧态”,磷已在晶界大量偏聚,钢已明显脆化;经阶梯冷却脆化处理后,晶界磷浓度成倍增加。在阶梯冷却脆化期间,Ni-Cr钢中磷的晶界偏聚速率比Cr-Mn-Si钢大。试验钢的FATT与晶界含磷量成正比;Ni-Cr钢中晶界Ni与磷呈线性关系。试验钢中加入La能够减少相同状态下的晶界磷浓度,从而改善钢的回火脆性。     

Ca对60CrMnCuV钢中硫的晶界偏聚及冲击韧性的影响

本文研究了微量Ｃａ对６０ＣｒＭｎＣｕＶ钢回火马氏体室瘟冲击的影响，并用Ａｕｇｅｒ能谱分析了沿晶口表面的Ｃａ及其它元素含量。结果表明，微量Ｃａ明显提高６０ＣｒＭｎＣｕＶ钢回火马氏的室温击韧性。Ａｕｇｅｒ能谱分析表明，Ｃａ在奥氏体晶界有明显的偏聚，促进Ｃｒ的偏聚，抑制硫的晶偏聚。认为Ｃａ抑制硫的晶界偏聚作用是韧化的重要原因。     

微量溶质元素在金属晶界的偏聚

溶质元素在金属晶界的偏聚可以分为两类，即平衡偏聚和非平衡偏聚。本文回顾了这两类偏聚现象及其机理，着重讨论分析了有重要工程用途的三类典型的晶界偏聚：硼在奥氏体晶界的两类偏聚的实验规律及对硼钢淬透性影响；磷在奥氏体晶界的平衡偏聚及对钢回火脆性的作用，钢中的其他合金元素对磷的偏聚的影响；硼在多种金属间化合物的偏聚及对这些金属间化合物塑性的影响及其机理。     

2.25Cr-1Mo-0.25V钢焊缝冲击性能和显微组织分析

进行了2.25Cr-1Mo-0.25V钢的焊条电弧焊试验,测定其焊缝的成分和冲击吸收功,进行了金相及启裂源观察,对冲击吸收功较低的样品进行脱脆处理.结果表明,冲击吸收功较低的焊缝的Mn,Si,Mo及其杂质元素含量相对较高,Mn,Si,Mo等元素促进杂质元素在晶界上的偏聚,致使晶界性能变坏,断口以沿晶断裂为主,冲击吸收功降低,脱脆处理后,冲击韧性恢复说明焊缝存在高温回火脆性,导致高温回火脆性是由于杂质元素在晶界上的偏聚,因此研制焊条时要严格控制Mn,Si,Mo和杂质元素的含量.     

EFFECT OF P ON IMPACT TOUGHNESS OF Cr-Mn-Si STEEL

用系列冲击试验法研究了30CrMnsiA钢在常规热处理工艺条件下,不同磷含量与冲击韧性的关系.试验结果表明,当磷含量≥0.012wt-%时,随磷含量的增加,冲击韧性明显下降.扫描电镜和Auger能谱分析发现,随磷含量增加,沿晶断裂面积及晶界上磷偏析增加.回火后缓慢冷却促进磷向晶界偏析,并使低温冲击韧性显著下降.550℃为本实验钢的高温回火脆性温度.     

磷对Cr-Mn-Si钢冲击韧性的影响

用系列冲击试验法研究了30CrMnsiA钢在常规热处理工艺条件下,不同磷含量与冲击韧性的关系.试验结果表明,当磷含量≥0.012wt-%时,随磷含量的增加,冲击韧性明显下降.扫描电镜和Auger能谱分析发现,随磷含量增加,沿晶断裂面积及晶界上磷偏析增加.回火后缓慢冷却促进磷向晶界偏析,并使低温冲击韧性显著下降.550℃为本实验钢的高温回火脆性温度.     

淬火冷速对H13模具钢组织及力学性能的影响

采用光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)研究了不同淬火冷却速度对H13热作模具钢显微组织及力学性能的影响。结果表明:当淬火冷却速度从12.6℃/min提高到40.7℃/min,经590℃回火6 h后,试验钢中的马氏体板条束宽度从340 nm减小至150 nm。此外,条带状及球状碳化物沿晶界的析出量显著减少;试验钢的室温冲击性能和硬度值均有一定的提高。试验钢以40.7℃/min淬火冷却+590℃回火6 h后在厚度方向的最低冲击吸收能量达到14.6 J;而试验钢以12.6℃/min淬火冷却+590℃回火后,晶界处合金元素偏聚严重,其中Cr、Mo和V元素含量分别高出基体约16%、23%和210%。     

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.     

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。     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

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.     

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.