热处理对新型坩埚熔炼的TiNi合金性能的影响

将自制的25kg级BaZrO3坩埚用于Ti-55.8%Ni合金(质量分数)的真空感应熔炼,并将合金铸锭经锻造、轧制、拉拔等工序制成φ1.0mm的TiNi合金丝材,取样经不同的制度热处理后,分析了TiNi合金丝材的拉伸性能、低周弯曲疲劳性能以及拉伸、疲劳断口形貌。结果表明:丝材经700℃保温1h水淬处理后,延伸率可达23%,韧窝尺寸变小、数量增多,且微孔数量大幅减少。此外,丝材经500℃或550℃保温20min水淬处理后,疲劳寿命得到提高,最高可达3072次,疲劳断口处贝纹线排列紧密,裂纹较短且部分存在分叉现象。     

钛合金熔炼用AZrO3（A=Ba,Sr,Ca）坩埚的制备及其使用性能研究

综述了3种新型复合氧化物(CaZrO3、SrZrO3和BaZrO3)坩埚的制备工艺,分析了3种坩埚熔炼TiNi合金后的效果和界面反应情况。合金熔体与耐火材料间无元素扩散,3种耐火材料均对合金熔体具有良好的反应惰性。此外,通过对比3种耐火材料坩埚与熔体间的界面反应层厚度,发现BaZrO3对TiNi合金熔体具有最高的化学稳定性。进一步使用BaZrO3制备成工业用25kg级坩埚并熔炼TiNi、TiFe、TiAl铸锭,发现铸锭杂质含量较低,说明BaZrO3是一种极具潜力的钛合金熔炼用新型耐火材料。     

Ti—46.5Al—3.0Nb—2.1Cr—0.2W显微组织对疲劳和拉伸性能的影响

高强度和低比重高温结构航空材料的需求,促进了高合铝量钛基合金的发展、Ti3 Al基合金显示出高的比强值和弹性模量,然而这组合金并不优于最高使用温度的常用钛合金(Ti—1100,IMI834),因此,目前人们的兴趣集中在γ-TiAl基合金上.过去对两相γ-TiAl基合金的研究,着重于提高塑性、变形断裂、蠕变特性和韧性方面,而对疲劳特性的研究却很少.J.Kumpfert等人研究了一种新的两相γ合金Ti-46.5Al-3.ONb-2.1Cr-0.2W的室温和高温拉伸及疲劳性能.试验中采用壳式熔炼和铸造技术,制备了直径为70mm的20kg铸锭,铸锭在1200℃/3h和138MPa压力的氨气气氛下(为消除孔隙)进行热等静压(HIP)加工.从铸锭切取120mm长的坯料,分两阶段在1150℃等温锻造,中间进行一次退火,得到φ24mm×10mm的饼材.用光学显微镜(OM)观察饼材边部和中心的不均匀显微组织,用热差分析法(DTA)及金相法测定了α转变温     

坩埚冷却系统改造对中间合金熔炼的影响

以Zr-Sn—Fe—Cr—Ni合金为研究对象,通过2次非自耗真空电弧熔炼制备出中间合金,对熔炼中间合金时所采用的坩埚的冷却系统进行了改造,对比了改造前后中间合金的熔炼过程,并采用OM、EDS研究了中间合金的组织及化学成分,冉以添加中间合金扣方式压制电极,利用真空自耗电极熔炼方式制备出吨级锆合金铸锭,并对成品铸锭的成分进行跟踪。结果表明：在坩埚中加入导流槽后,中间合金的熔炼效率得到了提高,熔炼时难脱模现象大大缓解;采用加导流槽后的坩埚经过2次熔炼可以制备出成分均匀的中间合金,合金组织由柱状品和树枝晶组成,与未加导流槽时所熔炼的合金相比,组织及成分更加均匀;采用冷却系统改造后的坩埚熔炼的中间合金可以制备出成分均匀的工业规模级锆合会铸绽。     

温压Fe-2Cu-0.5Mn-1C烧结材料超声疲劳研究

采用模壁润滑温压制备部分预合金Fe-2Cu-0.5Mn-1C烧结材料,设计材料的弯曲超声疲劳试样尺寸并研究对称弯曲超声疲劳行为,测试了材料在105~108周次下的疲劳性能。结果表明Fe-2Cu-0.5Mn-1C材料弯曲超声疲劳的条件疲劳极限存在,在106,107和108周次下相应的疲劳强度为402 MPa,331 MPa和273 MPa。疲劳裂纹一般在孔隙或夹杂物上萌生。超声疲劳断口的不同区域呈现出不同的特征。高疲劳应力时,裂纹源区位于靠近试样表面的孔隙或夹杂物处;低应力时,裂纹源区移动到材料亚表面或材料内部。裂纹扩展区出现了不规则分布的微观疲劳辉纹形貌,裂纹瞬断区中出现了解理面和韧窝等形貌。     

牙齿矫形用TiNi丝

对牙齿矫形用TiNi丝的合金成分作了选择。介绍了合金的研制过程、实验方法、机械性能、应力—应变曲线特征及临床应用效果等。我院研制的牙齿矫形用TiNi丝比目前广泛使用的不锈钢矫形丝回弹性能好得多、弹性模量低、刚度小、抗连续90°弯曲能力大,矫形效果好。其主要性能不亚于美国的Nitinol唇弓丝。     

TiNi合金粉末烧结与燃烧合成工艺

评述了目前用于制造TiNi合金的粉末冶金方法,包括粉末烧结和燃烧合成。近净成形粉末烧结可以保证成分均匀,晶粒细小。但是生产周期长,材料的纯度低。燃烧合成技术(SHS)是一种特殊的粉末冶金技术,兼有烧结与熔炼方法的优点,有望成为TiNi合金生产的主要手段。     

FGH95镍基高温合金粉末中的夹杂及其对合金疲劳性能的影响

本文系统研究了FGH95粉末高温合金的原始粉末和粉末处理过程中夹杂的性质 (成分、分类和形貌 )以及夹杂对材料低周疲劳性能的影响 ,建立了夹杂的位置和尺寸与LCF性能的关系曲线。     

GH586合金高温下低周疲劳断裂行为

研究了GH586合金在750℃下的低周疲劳性能,并对疲劳断口进行了电镜观察和分析.结果表明GH586合金低周疲劳裂纹源主要在合金表面形成,而且容易形成多个裂纹源;合金断裂存在脆性,断裂形式主要为晶间断裂.     

氢含量对新锆合金室温循环变形行为的影响

NZ2是我国自行研制的具有自主知识产权的新型Zr-Sn-Nb系锫合金,其堆外性能,尤其是耐蚀性能已达国外新合金同等实验条件下的相同水平,是十分具有应用前景的新锆合金.锆在反应堆中服役时会与冷却剂反应而吸氢,从而使锆合金的性能降低,导致失效.通过应变控制的对称拉-压(εR=εmin/εmax=-1)疲劳实验研究了不同氢含量(未渗氢,200,450.730μg·g-1)对NZ2新锆合金的室温低周疲劳性能以及氢含量对材料循环硬化及软化的影响,发现随着氢含量的增加,相同应变下材料的低周疲劳寿命下降,但达到某一饱和值的时侯材料的低周疲劳性能不再降低,随着氢含量的增加,材料有循环软化趋势,NZ2锫合金台氢试样比无氢试样更容易出现循环软化现象.     

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。     

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。     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

参与式农业基地建设行动方案设计

为了编制实用性强的基地建设行动方案,首先,确定参与式发展的主体,搭建一个"决策框架";其次,针对行动目标,提出不同参与主体,如管理者、农民、消费者等团队与个人的目标及行动内容;最后,工作应向重塑伙伴式合作关系,挖掘农民自我发展潜力,完成三大角色的转换,打造农业基地文化等方向推进.