高温注氢对钒合金微观结构的影响

研究了500℃高温条件下注氢对V-4Cr、V-4Ti和V-4Cr-4Ti三种合金微观结构的影响.在注氢实验之前,V-4Cr合金的基体清晰干净,而V-4Ti和V-4Cr-4Ti两种合金的基体中则出现很多相互平行和垂直的针状析出相,且大部分析出相周围都存在着位错.在500℃注氢实验之后,V-4Cr合金基体中出现大量的分布不均的黑色点状缺陷和缺陷簇,而V-4Ti和V-4Cr-4Ti两种合金的基体中除产生点状缺陷外,还出现高密度的气泡,且V-4Cr-4Ti合金中气泡的平均尺寸要稍小一些.另外,V-4Ti和V-4Cr-4Ti合金基体中原有的析出相在注氢实验之后都发生不同程度的溶解.在观察V-4Cr-4Ti合金基体中气泡分布规律时发现,在距离晶界25 nm的范围内几乎看不到气泡的存在,由此推断晶界的存在可以抑制氢气泡等辐照缺陷的产生.      

V-5Cr-5Ti合金再结晶规律及其动力学

研究了V-5Cr-5Ti合金在900～1100 ℃之间的再结晶规律, 概括了V-5Cr-5Ti合金的再结晶动力学机制. 结果表明, 合金冷变形板材在950～1050 ℃下退火处理, 可获得细小、均匀的等轴晶; 初步推导了V-5Cr-5Ti合金再结晶动力学机制, 符合Avrami-Erofeev形核长大机制; 并计算了V-5Cr-5Ti合金再结晶激活能Q_r, 其值为261.91～289.67 kJ· mol~(-1).     

Ti和Ag元素添加对Cu-Cr系合金微观组织及力/电性能影响研究

以Cu-0.5Cr和Cu-0.5Cr-0.1Ti-0.1Ag合金为实验材料，研究同时添加Ti和Ag元素对Cu-Cr系合金微观组织及力/电性能的影响。结果表明，Cu-0.5Cr和Cu-0.5Cr-0.1Ti-0.1Ag两种合金在450 ℃×1 h退火时达到峰时效状态，且Ti和Ag元素的加入显著提高了Cu-Cr系合金的硬度，但导电性能有所降低。同时研究了两种合金的高温抗软化行为，发现软化过程伴随着晶粒回复和再结晶，Ti和Ag元素的添加提高了Cu-Cr系合金的再结晶活化能，延缓了软化过程中合金的再结晶过程，使得Cu-0.5Cr-0.1Ti-0.1Ag合金的抗软化温度比Cu-0.5Cr合金提高约25 °C。     

时效处理对Cu-Cr-Ti合金组织与性能的影响

由于高强、高导Cu-Cr-Zr合金在工业化生产熔炼时不易控制Zr的收得率,通过采用Ti替代Zr,以期获得易熔炼以及性能与Cu-Cr-Zr合金相当的时效强化型Cu-Cr-Ti合金。采用真空感应熔炼技术,经过热锻、固溶、冷轧、时效共4道工序,制备了Cu-Cr-Ti合金板材;对时效后的Cu-Cr-Ti合金的组织状态、析出相形态、析出相与基体的界面关系进行了分析;对合金的抗拉强度和导电率进行了测试。结果表明:450℃时效60 min后,Cu-0.45Cr-0.14Ti合金的综合性能最佳,抗拉强度和导电率分别达到620 MPa和64.9%IACS;Cu-0.45Cr-0.14Ti合金中纳米尺寸的Cr强化相呈现椭圆形和双花瓣形,2种形状的析出相粒子均为面心立方结构,且均与基体保持完全共格关系。     

钒合金的电子辐照损伤研究

在室温(20℃)和高温(450℃)下,使用1 m V-高压透射电子显微镜(TEM)原位观察了V-4Cr-4Ti合金微观组织结构的演化和点缺陷团簇行为。原位电子辐照诱导Ti-C-O析出物发生分解,并引入缺陷团簇。这些缺陷团簇捕获电子辐照引入的点缺陷,随着辐照剂量的增加而单调长大。分析这些缺陷团簇平均尺寸与辐照剂量的依赖关系发现:当辐照剂量高于1 dpa时,缺陷团簇的长大速率小于辐照剂量低于0.5 dpa时的速率,说明V-4Cr-4Ti合金中缺陷团簇的长大速率随着辐照剂量的增加而减小。167℃下,运用电子加速器对V-4Cr-4Ti合金进行了离位电子辐照实验,采用小冲杆实验法(SPT)对电子辐照前后V-4Cr-4Ti合金样品进行了力学性能测试。发现相比于未经电子辐照的钒合金样品,经过电子辐照的钒合金样品开始发生塑性形变的位移减少了0.04 mm,说明经过电子辐照后,合金发生了延性损失,塑性降低。随着电子辐照剂量的增加,钒合金样品的最大断裂载荷和断裂韧性均单调增加。     

退火对V-4Cr-4Ti合金微观组织结构的影响

为了解高温退火前后V-4%Cr-4%Ti(记为V-4Cr-4Ti,下同)合金微观组织结构的变化,将合金在1000～1400℃,1×10-2Pa条件下退火不同时间(1h或3h)后,利用透射电子显微镜(TEM)分析了退火前后合金中位错、层错及孪晶的形态。分析结果表明,铸态合金中含有少量的层错和孪晶,但位错密度较高。高温退火后合金中的位错密度降低,层错、扩展位错的密度增加。孪晶密度随退火温度和退火时间的增加而增加。1200℃退火合金中的层错呈现规则的平行排列,层错使得基体衍射点发生分裂;孪晶的孪生面为钒的{211}晶面。在1300℃/3h退火合金中观察到了由大量微孪晶和位错组成的类"马氏体"结构。     

热处理对添加少量Cr、Fe的Ti-Ni合金组织和力学性能的影响

采用真空熔炼法制备Ti_(45)Ni_(55)Cr_(0.3)和Ti_(45)Ni_(52)Fe_3合金(元素含量为摩尔分数)铸锭,对其进行均匀化处理以及850℃/1 h固溶和水淬后,分别采用3种不同的工艺进行热处理:1)850℃/1 h固溶,2)375℃/1 h时效,3)25%冷轧+375℃/1 h退火,研究热处理工艺对合金的相变特性、力学性能、内耗性能和微观组织的影响。结果表明,Ti_(45)Ni_(55)Cr_(0.3)和Ti_(45)Ni_(52)Fe_3合金的基体均由B2与R相组成;Ti_(45)Ni_(55)Cr_(0.3)合金经过375℃/1 h时效或25%冷轧+375℃/1 h退火处理后,析出Cr3Ni2粒子,时效后抗拉强度为1 385 MPa,时效升温过程的峰值内耗达到0.53;Ti_(45)Ni_(52)Fe_3合金经过25%冷轧+375℃/1 h退火后析出Ti3Ni4相,抗拉强度为770 MPa;与其它热处理工艺的升温过程相比,Ti_(45)Ni_(52)Fe_3合金的时效升温过程峰值内耗最高,达到0.158;降温过程中,Ti_(45)Ni_(55)Cr_(0.3)合金在时效降温过程中发生B2→R→M相变,退火的降温过程中发生B2?R相变,而Ti_(45)Ni_(52)Fe_3合金在退火的降温过程中发生B2→R→M相变。     

热处理对大变形Cu-15Cr-0.1Zr合金组织和性能的影响

采用扫描电子显微镜、透射电子显微镜对Cu-15Cr-0.1Zr合金的铸态组织、变形组织和析出相进行观察,研究析出相、加工硬化、回复和再结晶对合金抗拉强度和电导率的影响。结果表明,中间退火能够大幅度提高Cu-15Cr-0.1Zr合金的电导率,并使电导率在后续冷变形中保持不变;同时析出的纳米沉淀相引起的沉淀强化作用能够部分抵消中间退火导致的抗拉强度的降低,使合金保持良好的抗拉强度;第一次中间退火温度采用500℃,后续中间退火采用450℃,能够使Cu-15Cr-0.1Zr合金具有优异的抗拉强度和导电性能。     

快速凝固Al-Cr-Zr-Ti合金的显微组织

利用透射电镜和能谱分析研究了Al-4Cr-4Zr-2Ti(原子数分数)合金急冷态和各种退火态的显微组织。急冷态为完全过饱和固溶体;350℃×4h处理后,晶界出现连续析出相;450℃×4h处理后,组织出现二种析出相晶界析出球状亚稳相Ll     

形变热处理对Cu-0.3Cr-0.1Zr合金上引铸坯杆组织性能的影响

通过对上引Cu-0.3Cr-0.1Zr合金固溶处理、冷拉拔以及随后的时效处理工艺,研究冷拉拔形变及时效对材料力学性能、导电性能及组织结构的影响规律.结果表明:时效前的冷拉拔变形能提高Cu-0.3Cr-0.1Zr合金的力学性能而保持较高的导电率;合金在950℃固溶1 h后,经70%冷拉拔变形和500℃时效4 h,合金抗拉强度和导电率分别达到了418 MPa和87%IACS;时效合金组织转变过程为:固溶体G.P.区Cr+Cu4Zr,析出相对位错运动的阻碍是合金强化的重要机制.     

Chinalco Signed Framework Agreement for Strategic Cooperation with Harbin Municipal Government

正Last month,Chinalco signed framework agreement for strategic cooperation with Harbin Municipal Government in Harbin Xiong Weiping,Chairman of Chinalco,said that based on the strategic deployment to build world top-class mining company with the highest growth potential,Chinalco was now concentrating all efforts on making strategic transition and structural adjustment,strategic cooperation with the local governments where     

Jiangxi Promotes Jiangxi Copper Corporation To Become The World's Most Competitive Mining Company

<正>According to the latest info from Jiangxi Province State-owned Assets Supervision and Administration Commission,Jiangxi Copper Corporation was approved to become the first pilot enterprise for deepening reform.Contents of the pilot work is"Three Self"(self expansion,self decision-making,self     

Journal of Rare Earths Contents List of Vol.32(2014)

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Contributions to Baosteel Technical Research wanted

正Baosteel Technical Research,a quarterly journal,which is issued domestically and abroad,is run and sponsored by Baosteel Group Corporation.Baosteel Technical Research mainly reports the achievements in technological innovation,academic research,new product development and industrial equipment improvement by Baosteel.It will continue to follow up on hot topics and serve the company’s technological development and progress.Its readers include experts in     

Ministry of Industry and Information Technology: No Short Term Solution For Our Country’s Excess Nonferrous Metal Smelting Capacity

【正】According to the Ministry of Industry and Information Technology,the Ministry has released the 2013 Operation Report on China’s Industrial Communication Indu...     

Chinalco Signed Framework Agreement for Strategic Cooperation with Gansu Province

正Recently,Chinalco and Gansu Provincial People’s Government signed"Framework Agreement for Strategic Cooperation on Reform,Restructuring and Transition Development of Chinalco’s Electrolytic Aluminum Enterprises in Gansu",signifying that the strategic cooperation between Chinalco and Gansu Province had made new substantive progress.     

Unavoidable Economic Cycle:30% Of Nonferrous Metal Companies Were Involved In Restructuring

正Owing to continual downturn in real estate and bulk commodity markets,a number of traditional industries in China suffered unfavorable impact in performance.With the progressive disclosure of third quarter report,the no-pleasant-surprise performance of     

Baotou Rare Earth Became the World's Biggest High Performance Magnetic Material Base

正The High Performance Magnetic Material Phase II Project,an industry upgrading project implemented by Inner Mongolia Baotou IronSteel Rare Earth(Group)Hi-tech Co.,Ltd,recently basically finished equipment commissioning,signifying that the enterprise had developed the production capacity of15000 t/a Nd-Fe-B strip casting alloy and 5000t/a Nd-Fe-B magnet,thus becoming the world’s     

Introducing Two Central Enterprises to Integrate Rare Earth Industry,Shandong Rare Earth Group Breaks Surface

正With the signing of"Letter of intention for Propelling Integration of Shandong Rare Earth Enterprises"between Shandong Province Commission Of Economy and Informatization,China IronSteel Research Institute Group("China Steel Institute"),and China Rare MetalsRare Earth Co.,Ltd("China Rare Earth"),the"Shandong Rare Earth Group"jointly set up by the 3 units thus broke surface.On August 9,reporters of the China Economic Herald learned from Shandong Province     

Aluminium Production by Province or City in 2014

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