α_2＋B2相区等温锻造及热处理对Ti-22Al-25Nb合金组织和性能的影响

研究了Ti-22Al-25Nb合金在α2+B2相区等温锻造及不同制度热处理,其显微组织演变规律和室温、高温拉伸性能变化。结果表明:在α2+B2相区等温锻造后显微组织仍由等轴α2相颗粒、O相包裹着的等轴α2相、细小板条状O相与B2基体组成,与原始锻棒组织的区别在于等轴α2相颗粒发生溶解,数量减少,尺寸下降;等温锻造后再在O+B2相区固溶处理的,组织中等轴α2相颗粒分解,由等轴α2/O相颗粒、板条O相和B2基体组成,且随固溶温度升高,板条O相溶解,变粗、变短;等温锻造后经固溶加时效处理时,B2基体中析出二次针状O相,且随时效温度升高,二次针状O相变粗、变短,室温及650℃高温拉伸性能也随时效温度升高,表现为强度降低而塑性提高。     

热处理对B2相区等温锻造Ti-22Al-25Nb合金组织和性能的影响

研究了B2单相区等温锻造Ti-22Al-25Nb(原子分数)合金经不同固溶加时效热处理工艺处理后,其显微组织的演变和力学性能的变化。研究结果表明,随着固溶温度的升高,Ti-22Al-25Nb合金组织中一次板条状O相变短变粗,体积分数减小,有球化的趋势,在随后的时效过程中会析出更多的次生针状板条O相;拉伸强度也随固溶温度升高而增加,塑性略微提高,断裂主要以沿B2晶粒的解理面解理断裂或准解理断裂为主,呈现许多近似层状的解理小刻面,其微观形貌为微孔状的韧窝。     

时效工艺对Ti-26合金棒材组织和拉伸性能的影响

对经过790℃固溶处理后的Ti-26合金棒材进行了不同温度及时间的时效处理,研究了时效温度和时间对Ti-26合金棒材显微组织和拉伸性能的影响。研究结果表明:在450~550℃范围内,随时效温度升高,合金组织有针状α相弥散物析出。升温至510℃,相同时效时间内析出α相数量最多,高于510℃,部分析出α相开始溶解。合金时效处理10 h内,随时效时间延长,合金组织针状α相弥散物数量增加,且针状α相存在跨晶界长大现象。合金经510℃×10 h时效处理,α相形核和长大达到最佳匹配,Ti-26合金获得理想的强度和塑性匹配。     

时效处理对一种新型粉末高温合金组织和性能的影响

对一种新型粉末高温合金进行不同时效处理,观察析出相和显微组织,测试合金室温、高温(750、815℃)拉伸和高温(750℃/750 MPa、815℃/450 MPa)持久性能,分析不同时效处理对合金组织和性能的影响。结果表明:过高的二级时效温度导致γ′相发生Ostwald熟化,减弱了γ′相的强化效果,导致合金的室温、高温强度降低,持久寿命明显缩短。单纯的一级时效,导致二次γ′相未发生进一步长大,三次γ′相微量析出,合金的强度提高,高温塑性显著降低。试样经HT2制度热处理后,二次与三次γ′相匹配良好,γ′相尺寸适当,未发生熟化,强度略有降低,塑性明显提高,综合力学性能优异。     

Ti-5Al-10Cr合金棒材的时效响应研究

对固溶处理的近β型Ti-5Al-10Cr合金进行了不同温度和时间的时效处理,观察了时效处理后合金的显微组织,分析了合金的相组成,并对硬度及拉伸性能进行了测试分析。结果表明,随着时效温度的提高,析出α相的体积分数先增多后减少,合金的抗拉强度与α相体积分数有着同样的变化趋势;合金在低温长时间时效或高温时效时,会析出Ti Cr2相,时效温度较低时该相对合金硬度有一定贡献,随着时效温度升高,该析出相长大,对硬度的贡献下降。     

轻质Al-Mg-Li合金的微观组织与力学性能

采用熔炼和热挤压制备轻质Al-5.5Mg-2.0Li-0.1Zr-0.2Sc合金，利用X射线衍射仪、差示扫描量热仪、金相显微镜、扫描电子显微镜、显微硬度计及拉伸试验机对合金的物相组成、微观组织、力学性能及断口形貌进行检测分析，研究时效工艺温度（120 ℃和160 ℃）对合金微观组织和力学性能的影响.结果表明:Al-Mg-Li合金挤压后晶粒组织呈纤维状，存在一定数量的Al₃Li（δ′）和Al₂MgLi（S）相；经固溶和时效处理后，再结晶晶粒尺寸变大，主要析出相为δ′相S相；160 ℃时效处理容易加速时效析出行为，导致析出相粗化，强化效果减弱；经120 ℃/20 h峰时效处理后，合金的抗拉强度、屈服强度和延伸率分别达到532 MPa、475 MPa和4.4 %.      

固溶时效工艺对GH4169高温合金组织和性能的影响

本文通过GH4169合金在不同热处理工艺条件下的固溶和时效处理实验,研究了固溶温度和时效温度对合金的微观组织和性能的影响。结果表明:720℃时效处理工艺下,1050℃以上固溶处理,晶粒明显细化,1100℃下晶粒最细,随着固溶处理温度的升高,时效析出的第二相含量增加;620℃时效处理工艺下,1050℃固溶时效析出相的含量最多,高于1050℃固溶并时效后的显微组织均比未经处理的组织细小;在1000℃进行固溶并经时效处理后材料获得的显微硬度最高,在1050℃以上随着固溶处理温度的升高,固溶时效硬度下降。     

长期时效温度对一种单晶高温合金组织和拉伸性能的影响

在定向凝固炉中采用螺旋选晶法制备了一种单晶高温合金试棒,标准热处理后分别在980 ℃,1 070 ℃,1 100 ℃和1 140 ℃长期时效处理500 h,研究了不同温度长期时效后合金的显微组织和1 100 ℃的拉伸性能.结果表明合金在不同温度长期时效后,γ′相发生粗化或筏排化.随着时效温度增加,γ′相粗化或筏排化程度增加,γ′相体积分数减少,γ相基体通道变宽.在980 ℃长期时效500 h后,无TCP相析出;1 070 ℃,1 100 ℃,1 140 ℃长期时效500 h后,有针状TCP相析出.随着长期时效温度增加,TCP相含量增加.随着时效温度升高,合金拉伸强度降低,拉伸延伸率先增加后在1 140 ℃时效时又降低.长期时效后γ′相粗化或筏排化、γ′相含量减少和TCP相析出是合金拉伸强度降低的主要原因.      

热处理工艺对注射成形IN713C合金组织与力学性能的影响

以气雾化IN713C合金粉末为原料,采用注射成形工艺制得合金材料,分别在1 150,1 175和1 200℃下进行固溶处理,然后在760,850和930℃进行时效热处理,通过扫描电镜(SEM)及能谱仪对合金的显微组织与物相组成进行观察与分析,并测定时效态合金的硬度与抗拉强度。结果表明:固溶温度达到1 175℃后,继续升高温度,则冷却过程中γ′析出相减少,固溶处理温度为1 175℃时合金的硬度(HRC)和抗拉强度分别为42.4和1175.9 MPa。时效处理温度为760℃时,合金的硬度(HRC)和抗拉强度分别达到43.6和1 223.7 MPa;时效温度高于760℃时,γ′相尺寸由于晶格错配度过大而粗化,随时效处理温度升高,γ′相尺寸逐渐增大,数量逐步减少,强化相体积分数降低,合金的硬度与抗拉强度都降低。注射成形IN713C合金的最优热处理制度为1 175℃/2h/AC+760℃/16 h/AC。     

固溶时效对TC4合金组织与机械性能的影响

研究了固溶时效对TC4合金的显微组织、室温力学性能、硬度、冲击韧性的影响。结果表明,经过α＋β区固溶处理＋530~760℃时效处理后的TC4合金显微组织分别为球状或条状初生α和转变β基体,随时效温度的提高,室温强度和硬度降低,塑性和冲击韧性无明显变化;β区固溶处理＋530℃时效处理后的TC4合金显微组织分别为魏氏组织和马氏体。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.