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针对近α型Ti?6.0Al?3.0Zr?0.5Sn?1.0Mo?1.5Nb?1.0V新型钛合金,在退火温度740 ℃的基础上,研究了退火时间对其组织与力学性能的影响。结果表明:经过3次真空自耗电弧炉熔炼,三火热轧后得到的板材组织由初生α相基体及β转变组织组成的部分再结晶组织和加工态组织等组成。随着退火时间的增加,退火板材的显微组织均以初生α相为主,且α相所占的比例从81.73%逐渐增加至85.61%,组织中长条状α相逐渐破碎球化,等轴α相开始均匀化、粗化。随着退火时间的增加,退火板材的延伸率逐渐增加,抗拉强度先降低再增加然后又降低,屈服强度先增加后降低,显微硬度先增加后降低。退火时间为1 h时,板材的断口由滑移带、涟波、小等轴韧窝组成,断裂方式为韧性断裂,退火时间大于等于2 h时,板材的断口完全由等轴韧窝组成,断裂方式为韧性断裂。最佳退火工艺为740 ℃退火2 h,此时板材的抗拉强度、屈服强度、延伸率和显微硬度分别为:984 MPa、941 MPa、15.27%、HV 347.67。研究结果对高强耐蚀钛合金退火工艺的制定有指导作用,为解决钛合金在实际生产中遇到的问题提供了科学依据。 相似文献
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采用模锻工艺及980℃退火工艺制备了Ti-6Al-3Nb-2Zr-1Mo合金,通过扫描电子显微镜(scanning electron microscope,SEM)观察和电子背向散射衍射(electron back-scattered diffraction,EBSD)分析等方法研究了退火态合金不同截面上的微观组织与力学性能。结果表明:与锻态合金比较,退火态Ti-6Al-3Nb-2Zr-1Mo合金的α相含量减少,亚稳态的β相增多。在空气冷却的过程中,合金的亚稳态β相又转化为次生α相和少量β相。退火态Ti-6Al-3Nb-2Zr-1Mo合金中α-Ti呈现出RD//[ī2ī0]、FD//[0001]的织构类型(FD为锻件压缩方向(锻造方向),RD为锻件自由延伸方向)。退火态Ti-6Al-3Nb-2Zr-1Mo合金的三个方向拉伸断裂主要是韧性断裂,并且断裂方式呈现出微孔聚集断裂。沿RD方向拉伸时韧窝尺寸较大,对应的延伸率也优于其他方向。 相似文献
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利用光学显微镜、透射电子显微镜、显微硬度计和万能拉伸试验机等分析手段,表征了Al?Zn?Mg?Cu?Zr?(Sc)合金搅拌摩擦焊(FSW)接头的显微组织和性能,探究了Sc元素对改善超高强Al?Zn?Mg?Cu?Zr合金焊接性能的作用机制。结果表明:Al?Zn?Mg?Cu?Zr?(Sc)合金焊接接头具有相似的组织特征,焊核区为动态再结晶组织,由细小均匀的等轴晶组成,包含较高密度的位错线,大部分时效析出相回溶;热力影响区晶粒被拉长,位错密度更高,残留的时效析出相显著粗化;热影响区保留与母材相同的晶粒形态,大部分时效析出的η'相发生长大,少部分粗化成η相。添加质量分数0.17%的Sc,可以使合金FSW接头抗拉强度提升43 MPa,屈服强度提升23 MPa,断后伸长率改善2.3%,焊接系数达到74.1%。Al3(Sc,Zr)二次析出相可以强烈抑制位错、亚晶界、晶界的移动,细化晶粒的同时保留大量的亚结构,且自身可发挥Orowan弥散强化作用。因此,可通过细晶强化、亚结构强化和弥散强化三种方式显著提高合金FSW接头的力学性能。 相似文献
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随着汽车保有量的提高,能源消耗和环境问题对汽车用钢提出了轻量化的要求。目前正在发展的第三代汽车用钢的研究思路是将加入轻量元素以“轻”和增强增塑以“薄”相结合。Fe?Mn?Al?C系中锰钢作为第三代汽车用钢的主要组成部分,是当今的研究热点之一。本文总结了近些年国内外Fe?Mn?Al?C系中锰钢的研究文献,从生产成本、力学性能等方面介绍了Fe?Mn?Al?C系中锰钢的优势。从成分设计、工艺设计、组织特征、变形及断裂机制等多个方面出发,对文献进行分析,总结出了合金成分、工艺路线和组织特征对性能的影响规律。阐述了奥氏体层错能及其稳定性对中锰钢变形机制,尤其是相变诱导塑性(TRIP效应)的影响规律。最后对目前Fe?Mn?Al?C系中锰钢研究过程中存在的争议问题进行了总结,展望了未来的发展趋势,以期为中锰钢的后续研究和实际生产提供参考。 相似文献
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《有色金属(冶炼部分)》1959,(1)
焙燒是土法煉铜的一項预备作业,它是使呈硫化物狀态存在的銅、鉄等氧化成氧化物的一个过程。焙燒时脱硫效率的高低是下一阶段鼓风爐冶煉实收率高低的一項影响因素。脫硫不完全,在冶煉时將产生冰銅,而冰銅又需返回破碎焙燒,增加处理工序,因此,如何提高焙燒时的脫硫率,是土法煉銅的一項关鍵問題。不論采用什么类型的焙燒爐,什么样的焙燒方法,为了使脱硫效率提高,都需使硫化物的矿粒充分暴露于空气气流中引起着火燃燒。当空气与受热的硫化物接触时,硫化物开始然燒,在矿石的着火溫度以下,CuSO_4大量生成。 溫度提高(600~650℃)、CuSO_4又分解为Cu_2O 相似文献
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Of all the many types of professional positions which psychologists are called upon to fill, one of the most demanding is that of functioning in an institutional setting. The psychological programs at such institutions are, generally, not the most advanced. The psychologist is called upon to function in a setting where the real contributions he can make are very often unknown. There is often a tremendous factor of professional isolation present--the feeling (and fact) of being cut off from professional colleagues and out of the mainstream of psychological life. To further compound the picture, institutional salaries are generally quite low. The present author, noticing these problems in his own state, helped initiate an annual meeting for these psychologists to share ideas of roles, functioning, program development, etc. The individual psychologists who participate, the psychological programs at the institutions, and the quality of service all seem to gain from this group. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Comments on the S. Rosenzweig et al article (see record 1963-04105-001), which examined the effectiveness of the foreign language requirements for the PhD degree in psychology. Publication data from American and foreign-language journals are discussed, showing that that European psychologists are familiar with our research but we are not with theirs. The author suggests that one possible way to break out of this isolationism would be that APA journals including American Psychologist give preference to papers discussing research which has not been published in English. Such a step would serve a double purpose: (a) American psychologists would become familiar with, and interested in, research by their non-English-speaking colleagues and (b) they would have an incentive for improving and using their knowledge of foreign languages. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献