两种铝锂合金薄板析出相及动静态性能比较

采用常规拉伸性能测试、中心裂纹疲劳裂纹扩展速率测试及透射电镜分析研究了2A97铝锂合金1.5 mm厚度薄板T3态(6%冷轧预变形后自然时效)及T8态(6%冷轧预变形+150℃)时效时拉伸性能、疲劳裂纹扩展速率和微观组织的演变,并与2050铝锂合金薄板性能进行了比较。结果表明:2A97铝锂合金冷轧薄板T3态时效时析出大量非常细小且共格的δ′相,合金具有中强(抗拉强度约427 MPa)耐损伤(ΔK=30 MPa·m~(1/2)时,疲劳裂纹扩展速率da/dN≈1.0×10~(-3) mm·cycle~(-1))的性能特性。而T8时效(12～40)时合金具有强度高(抗拉强度大于560 MPa)的性能特性。T8时效时强化相包括T1相(Al_2CuLi),θ′相(Al_2Cu)和δ′相(Al_3Li);欠时效时为一定数量δ′相及θ′相和大量细小的T1相;峰时效及过时效阶段, T1相逐渐长大,δ′相逐渐减少甚至消失,θ′相粗化且数量下降。2050铝锂合金薄板T3态时效时未发现时效析出相,其疲劳裂纹扩展速率与2A97铝锂合金相当,但强度明显较低; T8态时效时强化相T1相及θ′相数量少于2A97铝锂合金,因而其疲劳裂纹扩展速率相对较低,但强度也显著低于2A97铝锂合金。     

时效温度对1460铝锂合金薄板力学性能与微观组织的影响

采用拉伸性能测试及透射电镜(TEM)分析手段研究了1460铝锂合金薄板在145和175℃时效时的力学性能和微观组织的演化。研究结果表明:相比于145℃时效,1460铝锂合金175℃时效响应速率明显加快。在120 h时效时间范围内,175℃时效时合金的延伸率、最高抗拉强度以及屈服强度与抗拉强度差均低于145℃时效时,特别是175℃近峰时效时合金屈服强度与抗拉强度差明显降低。1460铝锂合金145,175℃两个温度时效时的主要脱溶产物均为δ'相(Al_3Li),合金时效初期均快速析出均匀弥散分布的δ'相;175℃时效时δ'相的粗化速度明显高于145℃时效,导致其尺寸随时效时间延长显著粗化,密度明显降低。145℃时效时随时效时间延长,合金在析出δ'相后形成大量的G.P.区;时效后期G.P.区长大,没有T1相(Al_2CuLi)的析出。175℃时效过程中合金在析出δ'相后快速析出T1相;时效后期T1相数量明显减少而尺寸显著粗化。     

时效制度对1441Al-Li合金抗腐蚀性能的影响

对固溶态1441Al-Li合金板材分别进行T6时效,以及5%冷轧预变形后再进行150℃时效,即T8时效处理,通过晶间腐蚀(IGC)、剥落腐蚀(EXCO)实验、极化曲线测试及透射电镜(TEM)分析,研究时效制度对1441铝锂合金的室温抗晶间腐蚀性能、抗剥落腐蚀性能及微观组织的影响。结果表明,合金经T6或T8时效处理后,随时效时间延长,合金微观组织由欠时效的晶内析出均匀的δ′相,变为晶内析出δ′相和S′相,以及沿晶界析出平衡相δ相和S相,因此合金抗腐蚀性能顺序为欠时效峰时效过时效。与T6时效态相比,经T8时效处理后,晶内析出的δ′相和S′相的数量增加、尺寸减小、分布均匀;同时,沿晶界析出的δ相和S相数量减少,PFZ变窄,合金的抗晶间腐蚀和抗剥落腐蚀能力提高。在3.5%NaCl溶液中进行的极化曲线测试表现出相同的结果。     

铝锂合金高强化成分设计

总结了铝锂合金高强化成分设计的发展过程,综合了课题组主合金元素Cu、Li含量,微合金元素Mg、Ag、Zn及稀土(RE)元素等对Al-Cu-Li系铝锂合金力学性能及析出相影响规律的研究结果。铝锂合金中Cu/Li比例较低时有利于时效时δ′相(Al3Li)析出,但不利于强度的提高;而Cu/Li比增加则有利于时效时T1相(Al2CuLi)及θ′相(Al2Cu)析出,从而有效提高铝锂合金的强度。微合金化元素Mg能有效促进T1相形核析出,加速铝锂合金时效响应速度,提高T1相析出密度,进而提高铝锂合金强度;Mg+Ag及Mg+Zn复合添加能进一步促进T1相析出,提高T1相分布密度;Mg+Ag+Zn三元复合微合金化具有最好的促进T1相形核析出及提高铝锂合金强度的效果。在高Cu/Li比铝锂合金中添加微量RE元素将导致时效时含Cu强化相T1相及θ′相减少,降低铝锂合金强度。铝锂合金高强化成分设计的思路应是在Mg、Mg+Ag、Mg+Zn或Mg+Ag+Zn微合金化基础上,提高Cu+Li总量并保持较高Cu/Li比。     

2297铝锂合金拉伸性能及强化机制

通过金相显微镜、扫描电镜和透射电镜观察以及拉伸性能测试,研究了95 mm厚2297-T87铝锂合金热轧板材1/2厚度层不同方向的显微组织和拉伸性能。结果表明:2297-T87铝锂合金在同一厚度层不同方向的拉伸性能具有明显的各向异性。强度规律为LT方向L方向45°方向ST方向;延伸率规律为L方向45°方向LT方向ST方向。L方向、LT方向和45°方向断裂方式均是以塑性断裂为主的混合型断裂,而ST方向则以脆性断裂为主。晶内主要析出相为板条状T_1相和针状θ′相,T_1相数量明显多于θ′相,是2297合金的主要强化相。     

对铝—锂合金薄板应变时效的研究

本文主要研究了2091合金薄板在预变形8%和12%,150℃和170℃不同时效时间下的组织和性能.随时效时间延长,时效温度升高,预应变增加,强度增加而塑性下降;时效初期合金主要断裂形式为穿晶断裂,随时效时间延长,沿晶断裂比例增大,这也是塑性下降的主要原因;时效时间延长,温度升高和预应变增加,δ’相析出增多长大,时效后期的s’相也析出增多,成为合金强化的主要原因;时效后期的S’相、共面滑移带和无析出区(PFZ)共同作用使塑性曲线下降平缓.     

Cd元素对Al-4Cu合金析出过程的影响

通过显微硬度、拉伸性能测试、透射电镜及高分辨检测等分析手段研究Cd在Al-4.0Cu合金中的微合金化作用。结果表明:100℃时效时,由于Cd元素的空位结合能较高,Cd元素的添加可抑制GP区的形成,减缓时效响应速率,使得含Cd合金的峰值硬度和强度降低;在150℃时效时,含Cd合金中析出的Cd′粒子为θ′相提供了非均匀形核位置,促进了θ′相的大量析出,使合金峰值抗拉强度大幅度提高。Cd′粒子与θ′相和铝基体的位向关系为(110)_(Cd)‖(001)_(Al)‖(001)_θ。     

稀土元素Ce对2090铝锂合金强塑性的优化作用

本文研究了稀土元素Ce以及时效温度和时间对2090铝锂合金室温拉伸强塑性的影响。结果表明,在2090铝锂合金中添加微量稀土元素Ce可显著改善其强塑性配合,对其断裂特征亦有影响,热处理制度相同时,2090+Ce合金室温拉伸断口上的滑移条纹多于2090合金。时效温度不同,合金强塑性和断裂特征随时效温度的变化规律亦不同。Ce对合金强塑性的优化作用亦受影响。时效温度较低和时间较短(欠时效至峰值时效)时,断裂方式为主断裂面穿晶断裂+短横向沿晶分层开裂的混合型,强度随时效时间延长而升高,但塑性随之下降。时效温度较高和时间较长(过时效)时,断裂方式主要为沿亚晶断裂,并伴有少量穿晶分量,此时强度和塑性均随时效时间的延长而下降。     

高温长期时效后Inconel718合金的化学相分析

采用化学相分析的方法研究了经过高温长期时效后标准Inconel 718合金中的析出相 ,确认了Inconel 718合金中α Cr相的析出 ,同时也分析了α Cr ,γ′ +γ″ ,δ相以及MC数量随时效时间和时效温度的变化情况。     

微量Ce对2090铝锂合金中δ'相析出长大行为的影响

:通过透射电镜分析、图像分析和统计分析等手段,对比研究了2090和2090 Ce两种铝锂合金中δ′(Al3Li)相析出长大行为的差异。研究结果表明:在190℃时效时,不含Ce的2090铝锂合金中球状δ′相长大行为与LSW理论模型符合较好,而2090 Ce中δ′相粗化过程却呈现出先快后慢的特征。时效初期(<3h),微量Ce对δ′相的析出有一定的抑制作用。本文分析认为这一特征是Ce原子与空位交互作用的结果。     

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。     

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.     

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.     

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.     

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)