G115钢650℃蠕变试验不同时间后的微观组织和硬度

对经1 100℃保温1 h空冷正火和710℃回火3 h的G115钢进行了650℃持续1 000、1 879、5 000和7 288 h的蠕变试验,检测了蠕变试验后钢的硬度和显微组织。结果表明:G115钢在650℃蠕变试验0～1 000 h内,硬度下降较缓慢,随着蠕变试验时间的进一步延长,硬度快速下降。正火和回火后,G115钢晶界和板条界析出了较多细小的粒状M23C6相,650℃蠕变试验后,晶界和板条界析出了较细小的粒状M23C6相和较粗大的块状Laves相,晶内析出细小的富铜相和MX相。蠕变试验0～1 000 h过程中有大量相析出,并随着蠕变时间的延长而长大。蠕变试验过程中,位错密度下降,马氏体板条变宽,晶粒长大,导致蠕变试验后钢的硬度降低。在蠕变试验0～1 000 h的过程中,由于有大量的相析出,钢的析出强化效果显著,部分弥补了位错强化和马氏体板条强化作用的减弱,因此硬度下降缓慢。析出相不仅影响析出强化效果,还阻碍位错密度下降和马氏体板条变宽,是影响G115钢650℃蠕变试验过程中硬度变化的关键因素。     

X12CrMoWVNbN10-1-1耐热钢的组织和高温力学性能

试验研究了X12CrMoWVNbN10-1-1耐热钢的显微组织和高温力学性能。结果表明:该钢经1075℃#1 h油冷淬火+570℃×4 h,空冷一次回火+720℃×2 h,空冷二次回火后的显微组织为典型的回火板条状马氏体组织,在原奥氏体晶界和板条界分布M23C6型碳化物,在马氏体板条内分布有纳米尺寸的MX相,此外还有少量在淬火加热时未溶解的尺寸达到0.6μm的残余MX相;在500～650℃范围内抗拉强度和屈服强度随试验温度的升高而降低,伸长率和断面收缩率随试验温度的升高而升高;持久强度与Larson-Miller参数P=T(25+lg(tf))/1000之间符合抛物线关系。     

长期时效对铸造ZG1Cr11Ni2WMoV马氏体耐热钢组织的影响

采用扫描电镜、透射电镜和金相显微镜研究了580℃长期时效对ZG1Cr11Ni2WMoV马氏体耐热钢显微组织的影响。研究结果表明:在1 050℃×1 h空冷淬火+580℃×2 h空冷回火后,存在纳米尺寸的M6C型碳化物弥散分布在回火马氏体板条上;580℃长期时效处理1 000 h,原奥氏体晶界和马氏体板条界上析出M23C6型碳化物,δ-铁素体中析出M23C6型碳化物和Laves相。     

铸造ZG1Cr11Ni2WMoV马氏体耐热钢的显微组织和力学性能

采用扫描电镜、透射电镜和X-射线衍射仪研究了ZG1Cr11Ni2WMoV马氏体耐热钢在不同热处理后的显微组织和力学性能。结果表明:铸态经580℃×2 h空冷回火后,显微组织由板条状回火马氏体和沿原奥氏体晶界分布的δ-铁素体组成,在δ-铁素体周围分布着连续网状的M_(23)C_6型碳化物,碳复型透射电镜分析发现在马氏体板条内分布有纳米尺寸M_6C-型碳化物;与铸态直接回火相比,经1050℃×1 h空冷淬火再经580℃×2 h空冷回火后,δ-铁素体含量减少且主要呈球状分布在回火马氏体基体上;1050℃×1 h空冷淬火处理对室温拉伸性能提高不大,但能显著提高室温冲击性能。     

热处理对9Cr低活化马氏体钢组织和力学性能的影响

研究了热处理对9Cr低活化马氏体钢显微组织和力学性能的影响.用光学显微镜和扫描电子显微镜观察了材料的显微组织、拉伸断口和冲击断口;用X射线衍射仪检测了材料的晶体结构.结果表明:9Cr低活化马氏体钢的晶粒尺寸从950℃的6.28μm增加到1200℃的66.5μm.两种热处理工艺(950℃×30min水冷+780℃×90min空冷和1050℃×30min水冷+780℃×90min空冷)处理后的9Cr低活化马氏体钢显微组织为全马氏体.二种工艺处理后拉伸力学性能相近,但冲击性能差别明显.二者的韧脆转变温度分别为-72℃和-62℃.选择950℃×30min水冷+780℃×90min空冷的热处理工艺能够提高9Cr低活化马氏体钢的冲击韧度.     

调整处理对A705-630不锈钢力学性能及显微组织的影响

对成分为0. 049%C、15.38%Cr、4.86%Ni、3.49%Cu、0.175%Si、0.760%Mn和0.173%Nb(质量分数),尺寸为40 mm×40 mm×400 mm的A705-630不锈钢试样进行了不同工艺的热处理:①1 040℃×1.5 h油冷固溶处理,固溶处理后480℃×3 h空冷时效处理;②固溶处理后时效处理前740～850℃保温2 h水冷调整处理。热处理后,检测了钢的显微组织和力学性能。结果表明:与仅经固溶和时效处理的A705-630钢相比,经固溶、时效和调整处理的钢马氏体板条较细小,位向关系较明显,强度和硬度下降,冲击韧度提高,且随着调整处理温度的提高,钢的强度、硬度提高,冲击韧度降低。     

轧后冷却工艺对Si-Mn-Cr-Ni-Mo低合金超高强钢组织和性能的影响

设计了一种以无碳化物贝氏体为主要组织的1500 MPa级Si-Mn-Cr-Ni-Mo系超高强度钢,对比研究了实验钢轧后经空冷、先水冷至550℃后空冷和先水冷至450℃后空冷3种冷却工艺的显微组织和力学性能。结果表明:实验钢轧后直接空冷获得无碳化物贝氏体+少量M/A组织,先水冷后空冷得到无碳化物贝氏体+少量马氏体组织。组织中对性能尤其是韧性性能有显著影响的残留奥氏体薄膜的形貌和分布随冷却工艺的变化而变化,空冷冷却残留奥氏体薄膜分布在贝氏体铁素体板条间,先水冷再空冷冷却残留奥氏体薄膜不仅存在于贝氏体铁素体板条间,在板条内部也可以观察到少量细小的膜状残留奥氏体,分割贝氏体铁素体板条,起到了细化晶粒的作用,有益于实验钢力学性能的提升。先水冷至550℃后空冷,实验钢的抗拉强度可达1600 MPa,-20℃冲击吸收功为28 J,具有最优的综合力学性能。     

一种高铬耐热钢的显微组织和负蠕变现象

采用扫描电镜、X射线衍射和蠕变试验研究了一种高铬铁素体耐热钢Fe-0.02C-8.72Cr-0.45Mo-1.76W-4.18Co-VNbN的显微组织和蠕变性能.结果表明:经1100℃×1h正火和700℃×1h+750℃×1h两阶段回火处理后,实验钢的显微组织为板条状回火马氏体,在650℃时效过程中有Fe2W型的Laves相析出.在650℃、250 MPa条件下该钢出现负蠕变现象,初步分析得知该现象的产生与蠕变过程中相的析出和粗化等有关.     

热处理对铸造4Cr9Si2耐热钢显微组织和性能的影响

研究了热处理对铸造4Cr9Si2耐热钢的显微组织和性能的影响。结果表明:铸造4Cr9Si2钢在铸态下组织为板条马氏体,经860℃×2 h退火处理后,在铁素体基体上析出粗大粒状和条状M_(23)C_6型碳化物,硬度降低,但冲击吸收功很低;经1020℃×2 h空冷正火+720℃×2 h回火热处理后,随后的冷却速率对显微组织和冲击吸收功影响很大。采用炉冷方式冷却的4Cr9Si2耐热钢存在高温回火脆性现象,组织中有细小弥散碳化物析出,造成二次硬化,硬度较720℃回火后水冷的试样高,冲击吸收功低。     

原位观察深冷处理板条马氏体

在金相显微镜和原子力显微镜上对深冷前后的板条马氏体进行原位观察.采用20钢试样.经1100℃×4min淬火后,观察选定区域后拍照,随即进行不同保温时间及深冷次数的深冷处理.再在原选定区域观察拍照,比较板条马氏体显微组织结构的变化.并利用X射线衍射和显微硬度测量深冷前后马氏体晶格点阵常数和硬度的变化.结果表明,深冷处理使板条马氏体的微细结构碎化.马氏体中析出微细碳化物与深冷的次数和回复的温度有关.深冷处理使得板条马氏体的正方度c/a趋近于1,并使马氏体的显微硬度略有增加(1％～3％).     

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.     

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.     

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.     

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。     

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.