异步轧制对Mg-Gd-Y-Zn-Zr板材组织、织构和性能的影响

以Mg-Gd-Y-Zn-Zr挤压态合金为材料，采用同步轧制（SR）和异步轧制（DSR）工艺，通过光学显微镜（OM）、电子背散射衍射（EBSD）、 X射线衍射（XRD）宏观织构检测以及室温拉伸等手段研究了两种轧制方式下板材微观组织的演变、织构组态及力学性能。结果表明：经SR和DSR轧制后，大尺寸的变形组织由于剪切破碎作用被细小的再结晶组织取代，两种轧板表层组织都比中心层组织更加细小均匀；与SR轧板相比，DSR轧板残留的变形区组织很少，动态再结晶程度更高，组织更加均匀；由EBSD分析结果可知，SR和DSR板材的再结晶机制均为连续动态再结晶；SR板材内部存在大量的低角度晶界（67.8%），仍然存在15μm以上的大晶粒，动态再结晶程度不高；DSR板材低角度晶界比例大大降低（25.8%），晶粒尺寸分布均匀，动态再结晶程度较高；SR板材呈现基底织构的特征，织构强度达到13.9; DSR板材基极向横向（TD）和轧向（RD）呈现均匀发散状态，织构强度降低到4.8；相同轧制条件下，DSR板材的抗拉强度和屈服强度分别比SR板材高30.1 MPa和38.2 MPa, DSR板材的延伸率（8.7%）比SR板材...     

TaW12合金加工态电子束焊缝的力学性能研究

对3mm厚TaW12合金板材进行真空电子束对接焊,随后成功地将该板材冷轧减薄到2mm厚和1.5mm厚,表明TaW12合金电子束焊缝具有较好的冷加工性能。拉伸试验结果表明,单纯电子束焊接仅能使合金抗拉强度达到699.65~721 MPa,延伸率达到9.38%~13.15%,而1.5mm厚板材加工态焊缝的抗拉强度可达934 MPa,约为冷轧态1.5mm厚基材抗拉强度的93.8%~94.7%,延伸率达到8.0%~9.0%;所有被焊拉伸试样均沿焊缝中心处断裂。加工态电子束焊缝具有更高的强度和塑性,这是焊缝微观组织大大细化和冷轧制加工促进焊缝气孔闭合的结果。     

轧制变形量对Ti-45Al-7Nb-0.3W合金组织与性能的影响

利用X衍射分析(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、室温拉伸试验等手段,研究粉末冶金Ti-45Al-7Nb-0.3W(原子分数,%)合金包套轧制过程中的显微组织和力学性能的变化规律。结果表明:热等静压法态的Ti-45Al-7Nb-0.3W合金组织为近γ组织,主要由块状的γ相组成,同时包括少量的α2相及极少量的B2相。轧制后Ti Al合金板材为双态组织,B2相消失。随轧制变形量增加,合金板材强度增加,变形量为40%时,板材抗拉强度最大,达到955 MPa。继续增加变形量合金板材的力学性能有所降低。当变形量较小时,合金的塑性变形主要通过位错滑移和攀移来实现。随变形量增加,孪生和动态再结晶机制发挥作用。     

温轧FeCrAl钢退火组织演变对力学性能的影响

摘要：研究采用电子背散射衍射技术（EBSD）对温轧及退火态Fe-13Cr-4.5Al-2.2Mo-1.1Nb（质量分数,%）钢的织构、晶界类型和Laves相进行了表征,并讨论了对力学性能的影响。结果表明,300℃温轧变形,70% 的样品出现显著的变形不均匀组织,利用Taylor因子解释了不均匀变形特征,晶粒取向以变形织构α、γ和<100>//ND为主,比例分别为43.3%、39.0%和17.1%,屈服强度和抗拉强度为1298.1MPa和1371.6MPa,伸长率4%。750～800℃退火30～60min后,再结晶晶粒尺寸小于10μm,γ织构比例减少至11.9%～15.5%,此时屈服强度为790～860MPa,抗拉强度为840～890MPa,伸长率为20%左右。1000℃退火5min后再结晶晶粒明显长大,γ织构增加至39.1%,此时屈服强度、抗拉强度和伸长率分别为567.7MPa、800.7MPa和25.6%。1000℃时随退火时间增加,γ织构增加至50%以上,Laves相的钉扎是γ织构增加的原因。600℃温轧的微观组织和300℃温轧的类似,但屈服强度和抗拉强度略有下降,伸长率增加。     

含钪Al-Zn-Mg-Zr合金薄板材MIG焊接接头的组织与性能

采用新型Al-Mg-Sc-Zr焊丝对含钪Al-Zn-Mg-Zr合金薄板材进行MIG焊,借助显微硬度及拉伸性能测试、OM,SEM,TEM等检测手段对焊接接头的微观组织和性能进行研究。结果表明:焊缝区为典型的铸态组织;热影响区靠近焊缝一侧呈现大量细小等轴晶组织,靠近基材区为纤维状组织和少量再结晶组织;基材区为纤维状组织。焊接接头的显微硬度以焊缝为中心呈近似对称,且中心处硬度值最低;抗拉强度为481 MPa,屈服强度为320MPa,伸长率为10.1%,焊接系数约0.83。同时,焊丝和基材中微量的Sc和Zr元素在合金中形成大量细小且与基体共格的Al3(Sc,Zr)粒子,能显著细化晶粒组织,有效抑制再结晶发生,大大改善焊缝区的力学性能。     

横轧对6016铝合金组织及力学性能的影响

采用金相显微镜(OM)、X射线衍射(XRD)、电子背散射衍射(EBSD)、万能拉伸试验机等研究了横轧对6016铝合金的组织和力学性能的影响,并与常规轧制工艺进行了对比。结果表明:6016铝合金热轧板材具有较强的β取向线织构,冷轧后普通轧制板材织构表现出典型的"唇式"冷轧织构特征,横轧使得原位于β取向线上的织构经{011}322取向流向B'{011}111,S'{123}17 22 9和C'{112}110,弱化了强的形变织构,形成随机织构;6016铝合金冷轧板材表现为典型的纤维组织形状,而横轧板材晶粒沿轧制方向拉长的程度小于普通轧制板材;普通轧制6016铝合金板材再结晶织构组分以Cube和Cube+ND15为主,而横轧板材则形成了强的(φ_1=20°,Φ=30°,φ_2=0°)织构;T4态横轧板材的强度值、延伸率和杯突深度值(I_E)值高于普通轧制板材;T4态横轧板材的塑性应变比(r)值要高于T4态普通轧制板材,各向异性(Δr)值要低于普通轧制板材,表明横轧有效改善了6016铝合金板材的成形性能。     

铍材温轧过程中显微组织和织构演变规律的研究

采用电子背散射衍射技术(EBSD)对热压烧结铍锭在温轧过程中的显微组织和织构演变规律进行了研究。结果表明,温轧过程中的主要变形机制为滑移;随着轧制变形量的增加,晶粒逐渐拉长细化;在压下量为37.9%时,轧制铍板中的基面织构达到最大值,此后继续增加压下量,铍材内织构、晶粒尺寸及显微硬度均不再发生明显变化;铍材轧制中或轧制后都需要进行退火,退火工艺对铍板的基面织构有一定的弱化作用,可改善板材的内部组织结构,提高轧制性能。     

预热温度对等径角轧制6016铝合金织构及力学性能的影响

通过准静态单轴拉伸实验、金相显微镜(OM)观察以及X射线衍射(XRD)宏观织构测试手段研究了3种不同预热温度(20,210,420℃)对等径角轧制6016铝合金板材的微观组织、织构及力学性能的影响。结果表明:在20,210,420℃3个温度范围内,随着温度的升高,RT(轧制)态板材的Brass{011}211织构、Copper{112}111织构、S{123}634织构等形变织构取向密度和体积分数降低;T4P(固溶+预时效+自然时效)态板材的Cube{001}100织构的取向密度和体积分数逐渐降低,而斯密特因子逐渐升高,织构逐渐离散弱化。在420℃条件下,RT态板材发生动态再结晶,形变织构尚存,但取向密度和体积分数非常低,此外还出现了少量向再结晶织构转变的中间态织构;T4P态板材出现了少量的P{011}112织构、Goss{110}001织构和其他一些不常见的织构类型,各种织构强度较弱,没有强烈的再结晶织构,织构无序分布。在420℃条件下的T4P态板材具有良好的塑性和成形性,其δ29%,σ_(0.2)110 MPa,r≈0.75,Δr≈0.16。而T8X(固溶+预时效+自然时效+模拟烤漆硬化)态板材具有良好的烘烤硬化性能,其σ_(0.2)210 MPa,σ_b335 MPa。     

高温轧制对AZ31B镁合金组织和性能的影响

研究了高温轧制工艺对AZ31B镁合金微观组织、织构以及性能的影响规律.在轧制状态下,随着轧制温度从450℃升高至525℃,合金组织内部动态再结晶逐渐增多,孪晶数量不断减少,同时组织的均匀性也得到了改善,基面织构强度也呈下降的趋势.经350℃保温60min退火之后,合金板材内部发生了完全再结晶,孪晶组织消失,显微组织更均...     

变厚板热冲压前后组织及拉伸性能差异性研究

选取国内、外两种热冲压B1500HS材料并以此进行变厚板设计,研究了从10%-60%轧制压下量下,热冲压前、后组织及性能的差异。结果表明:热冲压前随压下量增加,晶粒尺寸逐步拉长变大,抗拉强度、屈服强度逐步增加,其中抗拉强度增幅初期与压下比例基本一致,后期随着加工硬化的加剧高于压下比例,延伸率在20%压下量以前急剧下降,后缓慢下降;热冲压后不同压下量的材料均能充分转化为马氏体组织,且晶粒尺寸表现一致,平行到垂直三个方向上抗拉和屈服强度表现基本一致,断后延伸率随轧制压下量的增加而略有下降;变厚板轧制压下量在60%以内基本不影响热冲压后的性能要求,热冲压前的机械性能标准不适用于评判变厚板材料。     

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。     

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.     

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.