Cu-0.6Fe合金时效过程小角X射线散射研究

利用小角X射线散射(SAXS)技术研究了Cu-0.6Fe合金在500℃时效过程中的析出相。结果表明,Cu-0.6Fe合金在500℃保温0~80min时,析出相的尺寸为4.5~5.9nm。通过透射电镜观测500℃×10min时效后试样组织,测得晶粒半径约为4.6nm,表明小角X射线散射法测量Cu-0.6Fe合金时效析出相尺寸是准确的,比透射电镜测量方法更具有统计意义和参考价值。     

Cu-Cr-Zr-Mg合金时效析出研究

通过能谱和透射电镜分析研究了Cu-0．3Cr-0．15Zr-0．05Mg合金的时效析出，在470℃时效4h形成了有序的原子排列，其化合物类型为CrCu2(ZrMg)；同时存在体心的Cr相和面心的Cu4Zr相，在晶界上有少量未溶的Cr粒子。细小弥散的析出相使合金的性能得以提高，470℃时效4h～6h，硬度和导电率分别达109～108HV，79％IACS～80％IACS。     

镁硅复合微合金化对高强高导铜铬锆合金时效过程的影响

采用中频感应熔炼炉制备了Cu-0.7Cr-0.15Zr和Cu-0.7Cr-0.15Zr-0.05Mg-0.02Si两种合金,研究了Mg、Si复合微合金化对Cu-Cr-Zr合金时效工艺参数、性能与析出动力学的影响。结果表明：Mg、Si复合微合金化提高了Cu-Cr-Zr合金的最佳时效温度,延长了保温时间,Cu-0.7Cr-0.15Zr合金的最佳时效工艺为410 ℃时效8h,Cu-0.7Cr-0.15Zr-0.05Mg-0.02Si合金的最佳时效工艺为430 ℃时效14 h。Mg、Si复合微合金化提高了Cu-Cr-Zr合金的强度与导电率,Cu-0.7Cr-0.15Zr合金最佳工艺条件下的强度为570 MPa、电导率为79.1%IACS;Cu-0.7Cr-0.15Zr-0.05Mg-0.02Si合金最佳时效工艺条件下的强度为595 MPa、电导率为80.4%IACS。Mg、Si复合微合金化改变了Cu-Cr-Zr合金Avrami相变动力学方程,减缓了时效析出过程。     

时效参数和变形量对Cu-Cr-Zr-B-RE合金组织与性能的影响

研究了时效参数和变形量对Cu-1．15Cr-0．05Zr-0．04B-0．02RE合金组织与性能的影响。结果表明：该合金经950℃固溶1．5h、50％冷变形后，在470℃时效1．5h可获得较高的硬度和电导率，分别为104．2HB和48．76％IACS；并通过扫描电镜、能谱及X射线衍射仪等检测手段，发现时效过程中析出物为单质Cr和Cu5Zr化合物。     

Mg-12Gd合金的时效析出行为

通过同步辐射小角度X散射实验方法(SAXS)、透射电镜(TEM)分析和维氏硬度测试,研究Mg-12Gd合金等温时效过程中的析出强化行为。结果表明:Mg-Gd合金时效过程中主要析出相为β′相,随着时效时间的增加,析出相的径向尺寸明显增大,宽度方向增加较小,逐渐演变成为椭圆形。175℃时效180 h时,析出相回转半径为12.9 nm;随着时效时间延长到360 h,析出相长大为13.4 nm;随着时效时间继续延长,析出相的尺寸增长速率减慢并最终趋向稳定。透射电镜结果表明:在175℃时效296 h时析出相大部分为β′相,有少量的β″相,β′相是宽5 nm,长13 nm的椭圆形,与小角度X散射结果一致。通过在200℃时效30 min的散射曲线能看出有析出相析出,刚析出时回转半径为2.5 nm,在225℃时效30 min时,析出相的回转半径为2.9 nm。     

直流电流下Cu-0.33Cr-0.06Zr合金的时效动力学

采用固溶+冷变形+不同直流电流密度下的时效工艺制备了Cu-0.33Cr-0.06Zr(质量分数,下同)合金试样。进行了450℃下不同时效时间及不同电流密度的时效试验,研究了时效电流和时间对Cu-0.33Cr-0.06Zr合金导电性能的影响。采用透射电镜观察时效合金组织,探讨了不同电流密度下该合金的时效析出动力学。结果表明,合金在电流密度为100A/cm2的直流电流下时效,电导率低于无电流时效的;而在电流密度为400 A/cm2下时效2h后,电导率达到49.5MS/m,接近峰值,高于无电流时效的。时效后合金析出Cr相和CuZr3相,通过对电导率与析出相体积分数关系的分析,确定了合金在不同温度下时效的相变动力学Avrami经验方程和电导率方程。     

Cu-Cr-Zr-Sn合金的时效析出行为与性能

采用TEM对Cu-0.22Cr-0.05Zr-0.05Sn合金不同形变热处理状态微观组织的演变以及时效过程中析出相的状态进行研究,并以此解释形变热处理过程中合金力学性能和导电性能的变化.结果表明,合金中存在2种析出相,分别是Cr相和Cu4Zr相.其中Cr相在时效过程中分别经历了固溶体、GP区、脱溶并与基体共格以及长大;而Cu4Zr相则以早期Cr析出相为核伴随析出,与基体半共格.由于析出相尺寸很小,且分布较为均匀,使合金具有很强的时效强化效果,经940℃固溶1h后冷加工至变形率为96％并在400℃时效4h,合金的抗拉强度和电导率可分别达到400 MPa和84％IACS.对于该合金,时效温度是决定合金综合性能的关键,而时效时间对综合性能的影响并不显著.     

高强高导Cu-Cr-Zr合金时效性能

采用真空熔炼的方法制备Cu-Cr-Zr合金,研究合金的时效析出行为;借助高分辨透射电镜对合金时效析出相的组织形态进行分析,探讨合金的时效强化机制。结果表明:Cu-0.36Cr-0.03Zr合金经450℃时效4 h后获得较好综合性能,合金硬度和导电率分别达到为156 HV和82.62%IACS;通过微观分析确定经450℃时效4 h后合金中析出相为面心立方Cr相,且与基体保持共格关系;当时效时间延长至8 h时,合金中面心立方Cr相转变为体心立方Cr相;经450℃时效4 h后合金强度与硬度的提高主要由共格应变强化所造成。     

Cu-0.36Cr-0.03Zr合金时效析出相

利用透射电镜和高分辨电子显微镜对Cu-0.36Cr-0.03Zr合金时效处理后的析出相进行观察分析。结果表明,经450℃时效4 h后,合金显微硬度达到峰值,析出相为具有花瓣状应变场衬度的面心立方Cr相,与基体完全共格;当时效时间延长至8 h时,面心立方Cr相转变为体心立方Cr相;经550℃时效2 h后,合金显微硬度达到峰值,合金中弥散析出相呈球状,通过衍射花样标定,析出相为体心立方Cr相和Cu4Zr相,且Cr相与Cu基体之间存在N-W位向关系。     

固溶-时效对新型高强高淬透性热挤压Al-Zn-Mg-Cu-Zr合金组织与性能的影响

采用力学性能测试、金相观察（OM）、X射线衍射（XRD）、透射电子显微分析（TEM）研究了固溶-时效工艺对Al-6. 6Zn-1. 8Mg-0. 24Cu-0. 23Mn-0. 21Zr（wt%,7046A）合金挤压板带显微组织与力学性能的影响。结果表明:合金适宜的固溶-时效工艺为470℃×1 h固溶随后120℃×24 h人工时效。在此条件下,合金的抗拉强度、屈服强度和伸长率分别为570 MPa、532 MPa和10. 9%。T6态合金的物相组成为Al基固溶体、含Mn和Zr的初晶相以及3～5 nm的η’（MgZn₂）析出相,与此同时,晶界上析出η（MgZn₂）平衡相。合金的强化机制为固溶强化、亚结构强化和时效强化。      

Aging Precipitation Characterics of Lead Frame Cu-Cr-Zr-Mg Alloy

This paper presents the effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy. Optimal conditions for good hardening and electrical conductivity can be obtained by solution treating at 920℃ for lh and aging at 470℃ for 4h and at 550℃ for lh. The hardness and electrical conductivity can reach 108HV, 73%IACS and 106HV, 76%IACS, respectively. Aging precipitation was dealt with by transmission electronic microscope (TEM). At 470℃ aging for 4h the fine precipitation of an ordered compound CrCu2(Zr, Mg) is found in matrix as well as fine Cr and Cu4Zr. Aging at 550℃ for lh some precipitates are still coherent with matrix. The CrCu2(Zr, Mg) completely dissolves into Cr and Cu4Zr.     

热处理工艺对ITER级CuCrZr合金性能的影响

研究了同溶温度、时效温度和时间对ITER级Cu-0.8Cr-0.1Zr合金强化规律的影响和不同工艺下的金相组织,分析了合金导电率随时效温度的变化规律.结果表明:Cu-0.8Cr-0.1Zr合金硬度均随同溶温度、时效温度和时间的增加而呈现出峰值.在950℃同溶、480℃时效3 h后获得最佳硬化效果,硬度值为138 HV0.2.合金经同溶处理后的相对导电率仅为34%IACS,随时效温度的升高,导电率增加,480℃时效处理3 h,导电率达最大值74%IACS.     

Recrystallization and Precipitation Behavior of Cu-Cr-Zr Alloy

Recrystallization and precipitation behaviors after cold rolling and aging are investigated for Cu-0.7Cr-0.13Zr alloy. The processed alloy was characterized using the measurement of Vickers hardness, scanning electron microscopy, and transmission electron microscopy. The resultant complex microstructures are interpreted in terms of the interactions between precipitation and recrystallization. Upon aging at 500 °C for 1 h, the 45% rolled alloy exhibits a retarded recrystallization process and therefore an efficient hardening response, which are attributed to the pinning effect of fine dispersed precipitates on the dislocation. When heavily deformed and aged at high temperature, the alloy shows an accelerated process of recrystallization, and precipitates are found to coarsen.     

Aging characteristic of Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy containing trace rare earth yttrium

The aging characteristic of Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy containing trace rare earth yttrium was investigated. The results showed that Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy obtained good comprehensive performance after 80% rolling and then aging at 480℃ for 1 h; the hardness and electrical conductivity reached HV 150 and 85.5% IACS, respectively. Increasing aging temperature accelerated aging precipitation. The time for attaining peak hardness was postponed, the precipitates were finer (2-4 nm), and the interparticle spacing was shorter due to yttrium addition. The hardness and electrical conductivity of the Y-containing alloy after 80% deformation and then aging at 480℃ for 45 min reached HV 174 and 82.1% IACS, respectively.     

Effect of ball milling time on microstructures and mechanical properties of mechanically-alloyed iron-based materials

The microstructures and mechanical properties of an iron-based alloy (Fe-13Cr-3W-0.4Ti-0.25Y-0.30O) prepared by mechanical alloying were investigated with scanning electron microscope, optical microscope, X-ray diffractometer and hardness tester. The results show that the particle size does not decrease with milling time because serious welding occurs at 144 h. The density of the alloy sintered at 1 523 K is affected by the particle size of the powder. Finer particles lead to a high sintered density, while the bulk density by using particles milled for 144 h is as low as 70%. In the microstructures of the annealed alloy, large elongated particles and fine equiaxed grains can be detected. The elongated particle zone has a higher microhardness than the equiaxed grain area in the annealed alloys due to the larger residual strain and higher density of the precipitated phase.     

Analysis of precipitation in a Cu-Cr-Zr alloy

Precipites in Cu-0.42%Cr-0.21%Zr alloy were analyzed by using scanning electron microscope （SEM）, energy dispersive X-ray spectroscopy （EDXS） and transmission electron microscope （TEM）. After the solid solution was performed at 980℃ for 2 h, water-quenched and aged at 450℃ for 20 h, the precipite had a bimodal distribution of precipitate size. The coarse precipitates are pure Cr and Cu5Zr, the dispersed fine precipitate is CrCu2（Zr, Mg） and pure Cr ranging from 1 to 50 nm. The coarse phases formed during solidification and were left undissolved during solid solution. The fine precipitates are the hardening precipitates that form due to decomposition of the supersaturated solid solution during aging.     

Mg-Gd-Y-Zr合金的高温时效行为研究

通过金相显微镜、扫描电镜、X射线衍射等手段分析了金属型及砂型铸造Mg-Gd-Y-Zr合金高温下的时效析出行为.结果表明,经高温时效处理后,合金主要由Gd+Y在Mg中的过饱和固溶体、方块相、少量球状的Zr核及β相组成;高温时效处理几乎不影响合金的晶粒尺寸,随着时效温度的提高及高温时效时间的延长,合金的硬度逐渐降低;在晶内析出了呈三角取向或单一平行取向分布的β相,晶界上出现无沉淀析出带;成形条件并不影响高温时效析出相的分布和趋向.     

ITER级CuCrZr合金高能喷丸后的组织与强化机制

用X射线衍射仪、扫描电子显微镜、透射电子显微镜、显微硬度仪对经喷丸处理的Cu-0.8Cr-0.1Zr合金进行组织结构分析和硬化效果的测试,并在此基础上探讨了合金喷丸强化机制。结果表明,合金喷丸后在距表层300μm深度内形成了剧烈变形层和变形层两种不同变形程度的区域。其中剧烈变形层内位错密度较高,并形成位错胞亚结构和孪晶亚结构。随喷丸时间的增加,剧烈变形层晶粒尺寸可细化至80nm,表层HV硬度达到1.99GPa,较未变形试样提高1倍以上。合金的喷丸强化机制为细晶强化和应变硬化,而应变硬化的贡献大于细晶强化。