SiCp/6066Al复合材料的形变热处理研究

采用金相、布氏硬度、拉伸、DSC以及扫描电镜等研究手段研究了低温形变热处理对时效析出动力学、力学性能和拉伸断口的影响，以及时效时间对拉伸性能和拉伸断口的影响。结果表明，时效存在最佳时效时间，时效时间对力学性能和断口影响较大．其中以峰时效样品的强度和硬度最高，断口中的韧窝最小；固溶后的冷变形加速第二相的进效析出，变形程度越大时效析出速度越快，并且其力学性能越高，同时断口韧窝也越细小。     

Cu-Ni-Sn-P合金的耐热性能研究

对低浓度 Cu-Ni-Sn-P合金特征及预冷变形、热处理等工艺对合金耐热性能和热稳定性的影响进行了研究。研究表明,低浓度Cu-Ni-Sn-P合金具有固溶强化、时效析出强化及形变硬化多重强化特征,其析出强化粒子为Ni-P化合物,且在450℃ 30min时效时出现时效强化峰值现象;当冷加工率从25%提高到70%时,软化温度从500℃降低到400℃,450℃软化时间从50min缩短到30min;当冷变形加工率低于40%时,材料的热稳定性(450℃/1min)较好。     

时效处理对7075铝合金组织和性能的影响

对7075铝合金进行了单级时效处理和双级时效处理，表征了微观组织，测试了显微硬度。利用电化学工作站测试了腐蚀性能。实验结果表明：7075铝合金经120℃时效24h后，平均硬度为196HV；二级时效温度为160℃时，随时效时间的延长，硬度值基本呈现逐渐降低的趋势。7075铝合金经一级时效处理后，第二相析出产生时效硬化效果；在较高温度下进行二级时效，随保温时间的延长，时效析出相发生聚集、粗化和长大，降低了合金的硬度。随着二级时效时间的增长，合金的腐蚀电流先升高后降低，在二级时效16h、24h时合金的腐蚀电流最小，腐蚀性能最优。     

Al-2.3Cu-1.7Mg-1.2Fe-1.2Ni合金的时效行为研究

采用硬度测试、电导率测试、常温力学性能测试等方法研究了单级时效处理过程中时效温度和时效时间对Al-2.3Cu-1.7Mg-1.2Fe-1.2Ni合金力学性能和电导率的影响规律,并利用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、选区电子衍射(SAED)等手段对合金淬火态以及几种不同时效处理制度下的显微组织进行了研究.结果表明,合金经固溶淬火处理后仍残留有较多的大尺寸第二相,淬火态组织存在的第二相主要有Al9FeNi,Al7 Cu2 Fe,Al7 Cu4 Ni等.单级时效处理过程中,时效处理的温度越高,达到峰时效所需的时间越短,材料的峰时效硬度值越低;电导率随时效时间的延长而不断上升,时效温度越高,电导率的增长速率越快.峰时效条件下合金内主要沉淀强化相包括S’相和S"相,晶界上有明显的链状析出物存在,呈不连续分布;峰时效条件下,合金棒材的极限抗拉强度、屈服强度和延伸率分别为455 MPa,391 MPa和10.6％,电导率可达到21.6 MS·m-1.     

塑料模具用NAK80钢时效硬化工艺研究

通过对NAK80钢进行模拟时效实验,研究了时效温度以及时效时间对该钢硬化的影响,并对其硬化机理进行了探讨。研究结果表明,当时效温度为520℃、保温3 h以上时,硬化效果最佳。     

高强Cu-Ni-Co-Si合金时效分析及其相变方程

研究了Cu-Ni-Co-Si合金固溶后时效处理工艺对其导电率的影响,通过导电率与析出的第二相体积分数的关系推导了该合金的相变动力学方程.结果表明:随着时效时间的延长,导电率开始增加较快,4h时效后增速减慢;时效温度越高,时效初期导电率的升高速率越快,最终导电率也越高;时效过程中,导电率的升高率与第二相的析出量存在一定的线性关系.推导了该合金在500℃内不同温度下时效时的相变动力学方程和导电率方程,由该导电率方程所得的计算值与试验值相符.     

Ti-5Al-2Zr-2Sn-4Cr-4Mo合金时效强化特性

研究了Ｔｉ１７合金在相变点以下，经不同固溶温度处理、不同温度时效后亚稳β相的分解特性和硬化效应。结果表明，该合金在α＋β相区固溶处理，６３０℃附近温度时效，亚稳β相直接析出α相，具有较高的时效硬化速率。在时效初期，α相的含量随时间的增加而增加，而α相的形态经较长时间的时效方发生变化。最后，对α相的析出机制作了简要讨论。     

Cu时效硬化钢中Cu的析出

研究了Cu在工业试制的高强度船体钢中的时效析出行为及其时效硬化规律。结果表明：500～550℃时效,硬度随时间增加很快达到峰值,然后再降低;时效温度对Cu的硬化效果起决定性作用。1．5～2h时效硬化峰值温度约为500℃。在硬化峰值温度下,大量Cu析出相在位错线和板条界上析出,尺寸小于5nm,产生强烈沉淀强化作用。过时效状态下,Cu析出相发生明显长大,析出相形态由球状颗粒转变为杆状或短棒状,沉淀强化作用也随之减弱。     

Mo含量对AF1410钢二次硬化效果的影响

通过调整AF1410钢Mo的质量分数到3.0%,得到试验钢,对试验钢不同时效温度的性能进行了初步的研究.试验结果表明,与AF1410钢相比较,当Mo的质量分数为3%时,试验钢的二次硬化效果显著,在460 ℃时效时达到硬化峰值,峰值硬度为HRC 53.5,比AF1410钢的峰值硬度提高了1.5(HRC).     

Al-Cu-0.4Mg-0.6Ag合金的时效析出与力学性能研究

通过力学性能测试、差热分析及显微组织观察，研究了Cu的含量对Al-Cu-0．4Mg-0．6Ag合金的时效析出与力学性能影响。结果显示：增加Cu的含量，能提高基体合金的时效硬化与抗拉强度，其室温抗拉强度从434MPa增大到559MPa300℃时，合金的抗拉强度从141MPa增大到228MPa；185℃峰时效下，Al-Cu-0．4Mg-0．6Ag合金的主要强化相由片状Ω相和少量θ’相组成，随着Cu含量的增加，峰时效态合金中的Ω相体积分数增大。     

Theoretical nuances and practical old questions: The psychology of aging.

The dichotomy of theory and practice is discussed within the framework of the experimental psychology of aging, with particular emphasis on investigations of memory retrieval. Over-emphasis on theoretical nuances should be replaced by attempts to provide tentative answers to questions of importance to our aging population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-perceptions of aging predict mortality and change with approaching death: 16-year longitudinal results from the Berlin Aging Study.

Satisfaction with one’s own aging and feeling young are indicators of positive well-being in late life. Using 16-year longitudinal data from participants of the Berlin Aging Study (P. B. Baltes & K. U. Mayer, 1999; N = 439; 70- to 100-year-olds), the authors examined whether and how these self-perceptions of aging change with age and how such changes relate to distance from death. Extending previous studies, they found that it is not only higher aging satisfaction and younger subjective age but also more favorable change patterns (e.g., less decline in aging satisfaction) that are uniquely associated with lower mortality hazards. These effects are robust after controls for objective measures such as age, gender, socioeconomic status, diagnosis of dementia, or number of illnesses. As individuals approach death, they become less satisfied with their aging and report feeling older. For aging satisfaction, mortality-related decline is much steeper than age-related decline, whereas change in subjective age is best characterized as an age-related process. The authors discuss how self-perceptions of aging are embedded in mechanisms underlying pathways of dying late in life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Jack Botwinick (1923-2006).

This article presents an obituary for Jack Botwinick, a pioneering researcher and writer on the psychology of aging. Jack died February 12, 2006, in St. Louis, Missouri, after being diagnosed with inoperable lung and brain cancer in mid- December 2005. He is survived by his wife, Joan, three daughters, and four granddaughters, as well as the many colleagues and former students who benefited from his warm concern and valued advice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related differences in responses to thoughts of one's own death: Mortality salience and judgments of moral transgressions.

Two experiments explored age differences in response to reminders of death. Terror management research has shown that death reminders lead to increased adherence to and defense of one's cultural worldview. In Study 1, the effect of mortality salience (MS) on evaluations of moral transgressions made by younger and older adults was compared. Whereas younger adults showed the typical pattern of harsher judgments in response to MS, older adults did not. Study 2 compared younger and older adults' responses to both the typical MS induction and a more subtle death reminder. Whereas younger adults responded to both MS inductions with harsher evaluations, older adults made significantly less harsh evaluations after the subtle MS induction. Explanations for this developmental shift in responses to reminders of death are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examining inhibition of return with multiple sequential cues in younger and older adults.

Studies with younger adults have shown that when multiple peripheral cues are presented sequentially, inhibition of return (IOR) occurs at several locations with the greatest IOR at the most recently cued location and the least at the earliest cued location. The inhibitory ability needed to tag multiple locations requires visuospatial working memory, and it is thought that this type of memory may be vulnerable to the effects of aging. The present experiments examined whether older adults would show less IOR at multiple cued locations than younger adults when placeholders were present (Experiment 1) and absent (Experiment 2). Of interest, in both experiments older adults showed an almost identical pattern of IOR, in both magnitude and number of inhibited locations, to that of younger adults. This finding, in conjunction with research on memory-guided saccades, suggests that there may be a form of visuospatial working memory, specific to oculomotor and visual attention processes, that is relatively resistant to the effects of aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context Processing and Context Maintenance in Healthy Aging and Early Stage Dementia of the Alzheimer's Type.

Declines in the ability to process context information may represent a fundamental mechanism of age-related cognitive changes. Two components of context processing--activation/updating and maintenance--were examined in a sample of healthy younger and older adults, along with individuals suffering from early stage dementia of the Alzheimer's type (DAT). All older adult groups showed context activation/updating impairments, whereas context maintenance was only impaired in the oldest adults (age>75 years) and was further exacerbated in DAT individuals. The results suggest that context processing may be composed of functionally dissociable components and point to the utility of this construct in understanding the timecourse of cognitive decline in healthy and pathological aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging on absolute identification of duration.

Experiments to examine the effects of aging on the ability to identify temporal durations in an absolute identification task are reported. In Experiment 1, older adults were worse than younger adults in identifying a tone's position within a series of 6 tones of varied durations. In Experiment 2, participants were required to identify a tone's position in 9 tones of varied durations. Older adults' performance was again worse than that of younger adults; moreover, they showed a qualitatively different pattern of errors than younger adults. In Experiment 3, in which the tones varied in pitch, the performance of older adults was worse than that of younger adults, but the error patterns of the 2 groups were similar. The results suggest that older adults have distorted memory representations for durations but not for pitch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring the specificity of age-related differences in theory of mind tasks.

Tasks assessing theory of mind (ToM) and non-mental state control tasks were administered to young and older adults to examine previous contradictory findings about age differences in mental state decoding. Age differences were found on a verbal ToM task after controlling for vocabulary levels. Older adults achieved significantly lower scores than did younger adults on static and dynamic visual ToM tasks, and a similar pattern was found on non-ToM control tasks. Rather than a specific ToM deficit, older adults exhibited a more general impairment in the ability to decode cues from verbal and visual information about people. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

No protective effects of education during normal cognitive aging: Results from the 6-year follow-up of the Maastricht Aging Study.

Recent large-scale longitudinal aging studies question earlier claims that higher education protects against cognitive decline in older age. In the present study, the authors addressed this issue by determining whether educational level had an attenuating effect on the rate of cognitive change assessed with a broad range of neuropsychological tests in a community sample of 872 healthy individuals aged 49 to 81 years at baseline. The participants were followed for 6 years and were tested 3 times (at baseline and at 3 and 6 years after baseline). Results of linear mixed-model analyses showed that education had no significant effect on cognitive change over time. These results are discussed in terms of the age range of the sample, definition and range of education, cognitive measures used, length of the study and number of consecutive assessments, and confounding effect of health. The findings question the extent of the presumed protective effects of higher education on cognitive decline during normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)