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。     

Cu-Cr-Zr合金时效强化机理

研究了不同时效工艺对Cu-0．7Cr-0．13Zr合金硬度、强度和导电率性能的影响,利用透射电镜分析合金时效后的微观形态和析出相。结果表明：在500℃时效30min析出相为Cu5Zr,硬度和导电率可达116．7HV和47％IACS。500℃时效6h后,硬度和导电率为140HV和76％IACS,强度达到峰值430MPa,弥散共格的析出相Cr是强度提高的重要原因,强化效应与采用共格强化机理计算的结果非常接近。合金在500℃时效8h硬度和强度仍具有135．6HV和410MPa,导电率为77％IACS,析出相仍较细小但与基体失去共格关系。     

形变热处理对Cu-Ag-Cr和Cu-Ag-Zr合金组织和性能的影响

采用中频熔炼-铁模铸造-热轧-固溶-冷轧-时效处理工艺,制备了Cu—Ag-Cr和Cu—Ag-Zr两种合金板材。通过拉伸力学性能测试、电导率测试、金相和透射电子显微镜观察,研究了固溶-预冷变形-时效对加入微量Cr、Zr的Cu—Ag合金组织和性能的影响。结果表明：在Cu—Ag合金中添加微量Cr和Zr,能显著地提高铜银合金的力学性能,添加Cr时,电导率有-定降低,而添加Zr时,电导率没有明显变化;两种合金较好的形变热处理工艺为时效前进行30％冷变形,然后在450℃下时效4h,在此工艺条件下Cu—Ag-Cr合金的抗拉强度、伸长率、相对电导率分别为397MPa、16．8％和78％IACS,Cu—Ag-Zr合金的抗拉强度、伸长率、相对电导率分别为373MPa、10％和96％IACS;形变热处理能够显著提高研究合金的力学性能而不明显降低电导率,微量Cr、Zr以Cr单质和Cu3Zr粒子的形式在基体中弥散析出,是合金强度提高的主要原因,而纯铜的基体仍使其具有较高的电导率。     

快速凝固Al—4Cr—4Zr—2Ti合金的时效特性

利用透射电镜观察了Al-4Cr-4Zr-2Ti（原子百分比）合金的显微组织,并测定了相应的显微硬度。结果表明：快凝合金在400℃,4h时效达到峰值硬度,Hv达2420MPa,此时的析出相为Al13Cr2和与基体共格的亚稳相Ll2-Al3Zr。合金经400℃,96h时效后的显微硬度与急冷态硬度和峰值硬度相比仅分别下降10％和14％。而500℃,4h时效后,由于Ll2-Al3Zr转变为DO23－Al3Zr并且析出相粗化,导致合金硬度急剧下降。     

Cu-1.0Cr-0.2Zr合金的时效析出研究

研究了形变热处理及时效对Cu-1.0Cr-0.2Zr合金组织和性能的影响。结果表明:合金在960℃固溶2 h,经60%冷变形再在450℃时效4 h的综合性能最佳,合金的抗拉强度和伸长率分别为527.4 MPa和12.3%,电导率为82.1%IACS。合金的综合性能最佳归结于在基体上析出了两种细小且弥散分布的第二相,第一种相为铬相并以六边形和球状两种形态存在,第二种相为CrCu2Zr相,且这些弥散分布的第二相减缓了回复及随后的再结晶过程。析出相的逐渐析出,导致基体贫化并减弱了基体对电子散射的作用,使电导率恢复到较高的水平。     

含稀土Cu-Cr-Zr合金的微观组织和性能（英文）

先后热轧、固溶处理、冷轧和时效处理Cu-0.81Cr-0.12Zr-0.05La-0.05Y(质量分数)合金,并系统研究其不同阶段的微观结构、显微硬度和导电率的变化规律。合金铸态组织由Cu基体、Cr相和Cu5Zr三相组成。经固溶处理后,Zr相充分溶于Cu基体中,而部分Cr相仍残留于Cu基体中。样品冷轧后的时效处理使Cr与Cu5Zr纳米析出相从基体中析出,且基体显微硬度和导电率增加。在773 K时效60 min后,样品获得了高显微硬度(HV 186)和高导电率(81%IACS)。随着时效温度的提高,Cu晶体的取向度逐渐减小到零,而微应变因存在析出相和位错的相互作用未能得到完全的释放。当共格强化机制在合金中起主要增强作用时,Cr析出相与铜基体之间保持着N-W的位相关系。     

新型Cu-Zn-Cr合金的形变热处理及对性能的影响

设计了一种新型导电结构材料Cu-Zn-Cr合金。通过金相观察、硬度测量、电导率测量和透射电子显微分析(TEM)以及高分辨分析的方法,研究了形变热处理工艺对Cu-Zn-Cr合金性能的影响以及Cu-Zn-Cr合金的强化机理。结果表明,由均匀化、热轧、固溶、冷轧、时效组成的形变热处理工艺能显著提高合金性能;合金的最佳均匀化温度为900℃,最佳时效温度为400℃,最佳时效时间为1 h;960℃固溶处理2 h能提高时效强化效果。经过固溶处理后冷变形80%,再在400℃时效1 h后合金综合性能最佳,硬度为194 HV2,电导率为42%IACS。时效过程中Cr以纳米级的第二相粒子形式从过饱和固溶体中析出,产生沉淀强化效果,同时净化了基体,提高了电导率。     

形变热处理对Cu-2.7Ti-0.15Mg-0.1Ce-0.1Zr合金组织和性能的影响

利用力学、电学性能测试和透射电镜观察等手段研究了形变热处理对Cu-2.7Ti-0.15Mg-0.1Ce-0.1Zr合金组织与性能的影响。结果表明:合金固溶后于450℃时效8 h呈典型的调幅分解组织,还存在纳米级强化相β’-Cu4Ti。合金经固溶处理后,冷轧97.5%,在400℃时效1 h时显微组织主要为亚晶组织+纳米析出相,亚晶尺寸约为40 nm。形变热处理能够有效提高合金的综合性能,合金经过97.5%冷变形、于400℃/12 h时效后,硬度为301 HV、电导率为20.9%IACS。     

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。     

Effect of thermomechanical treatment on microstructure and properties of Cu-Cr-Zr-Ag alloy

The effects of thermomechanical treatment on the properties and microstructure of Cu-Cr-Zr alloy and Cu-Cr-Zr-Ag alloy were investigated. Ag addition improves the mechanical properties of the alloy through solid solution strengthening and brings a little effect on the electrical conductivity of the alloy. A new Cu-Cr-Zr-Ag alloy was developed, which has an excellent combination of the tensile strength, elongation, and electrical conductivity reaching 476.09 MPa, 15.43% and 88.68% IACS respectively when subjected to the optimum thermomechanical treatment, i.e., solution-treating at 920°C for 1 h, cold drawing to 96% deformation, followed by aging at 400°C for 3 h. TEM analysis re-vealed two kinds of finely dispersed precipitates of Cr and Cu4Zr. It is very important to use the mechanisms of solid solution strengthening, work hardening effect as well as precipitate pinning effect of dislocations to improve tensile strength of the alloy without adversely affecting its electrical conductivity.     

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.     

Age hardening characteristics of Cu-Ag-Zr alloy

Cu-Ag-Zr alloy is a newly developed copper alloy material which has an excellent combination of high mechanical strength and high electrical conductivity. By means of vacuum induction melting, Cu-Ag-Zr alloy was produced. The effects of aging processes on the microhardness and electrical conductivity characteristics of Cu-Ag-Zr alloy were studied. After aging at 450 °C for 4h, the alloy showed an excellent combination of microhardness and electrical conductivity: the microhardness and electrical conductivity reach 126 HV and 84%IACS, respectively. The precipitates responsible for the age-hardening effect are the fine and dispersed Cu₅Zr, which has a face center cubic structure. Cu₅Zr precipitates are fully coherent with the Cu matrix and give the Cu-Ag-Zr alloy higher microhardness and higher electrical conductivity.     

Effect of alloying elements on mechanical properties in Cu-15%Cr in-situ composites

The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15% (mass fraction) in-situ composites were systemalically studied and high strength and high electrical conductive Cu base in-situ composites have been developed. The best combination is the addition of 0.1% to 0.2% Zr, Ti, or Sn in Cu-15%Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of the second phase, and the fine Cr precipitates. The aging treatment to reduce solute atoms has a beneficial effect on the increase of electrical conductivity. The addition of Zr, or Ti of about 0. 15% to 0.2% promotes the precipitation of Cr particles.     

高强高导电CuCrZr合金时效过程中析出相的演化规律

对固溶态CuCrZr合金经不同温度时效后的析出相进行显微观察,并对其电导率进行了测试。结果表明:450 ℃时效30 min的析出相为5 nm以下的单质Cr相,并且与基体呈cube-on-cube取向关系。450 ℃峰值时效120 min时析出相为CrCu₂Zr相和Cr相,尺寸为10nm左右,且与基体共格;600 ℃和800 ℃过时效30 min后析出相主要演变为球状的Cr相和棒状的Cu₄Zr相。在600 ℃时效处理后部分棒状析出相已显著长大至50 μm左右,而800 ℃时效处理后几乎看不到细小的析出相,其中棒状Cu₄Zr析出相长大至200 μm以上,球状纯Cr析出相也接近50 μm。CuCrZr合金在450 ℃时效时导电率随时效时间的延长不断增高,在120 min后达到最大值且几乎不再变化。根据析出相转化率与导电率的线性关系,建立了合金在400、450、500和600 ℃下的析出动力学方程。     

等径角挤压对Cu-0.81Cr-0.07Zr合金第二相颗粒分布、硬度和电导率的影响

研究在室温和300℃下等径角挤压(ECAP)对Cu-0.81Cr-0.07Zr合金中第二相分布的影响,及其对硬度和电导率的影响。显微组织表征表明,经ECAP后,粗大的富Cr颗粒面积分数减小,这是由于塑性变形导致Cr的溶解。在室温下进行4道次ECAP后,由于固溶体中较高的Cr含量和基体中较高的缺陷密度导致电子散射的增加,合金的电导率下降了12%。仅在ECAP样品中观察到的Cu晶格常数的减小和差示扫描量热分析(DSC)过程中发生的放热反应证实了这些结果。经ECAP后的时效热处理促进额外的硬化效果和导电性的完全恢复,这是由于部分溶解颗粒的再沉淀造成的。在室温下进行4道次ECAP,然后在380℃时效处理1 h的合金具有更高的硬度(191 HV)和电导率(83.5%(IACS))。     

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。     

Microstructure and properties of aging Cu–Cr–Zr alloy

The crystallography and morphology of precipitate particles in a Cu matrix were studied using an aged Cu–Cr–Zr alloy by transmission electron microscopy(TEM) and high-resolution transmission electron microscopy(HRTEM). The tensile strength and electrical conductivity of this alloy after various aging processes were tested. The results show that two kinds of crystallographic structure associated with chromium-rich phases, fcc and bcc structure, exist in the peak-aging of the alloy. The orientation relationship between bcc Cr precipitate and the matrix exhibits Nishiyama–Wasserman orientation relationship. Two kinds of Zr-rich phases(Cu4Zr and Cu5Zr)can be identified and the habit plane is parallel to {111}Cu plane during the aging. The increase in strength is ascribed to the precipitation of Cr- and Zr-rich phase.     

Cr含量对时效态Cu−Cr−P合金显微组织和性能的影响

研究Cr含量对时效态Cu?Cr?P合金析出相和性能的影响.结果发现,时效处理后Cu?Cr?P合金中存在3种尺寸的Cr相,其中,纳米级Cr相是Cu?Cr?P合金的主要强化相;≤5 nm的Cr相为面心立方结构,与基体完全共格,强化机制为位错切过机制,强化效果约为200 MPa;10～20 nm的Cr相为与基体非共格的体心立...     

Effect of elevated-temperature annealing on microstructureand properties of Cu−0.15Zr alloy

Cu−0.15Zr (wt.%) alloy with uniform and fine microstructure was fabricated by rapid solidification followed by hot forging. Evolution of microstructure, mechanical properties and electrical conductivity of the alloy during elevated-temperature annealing were investigated. The alloy exhibits good thermal stability, and its strength decreases slightly even after annealing at 700 °C for 2 h. The nano-sized Cu₅Zr precipitates show significant pinning effect on dislocation moving, which is the main reason for the high strength of the alloy. Additionally, the large-size Cu₅Zr precipitates play a major role in retarding grain growth by pinning the grain boundaries during annealing. After annealing at 700 °C for 2 h, the electrical conductivity of samples reaches the peak value of 88% (IACS), which is attributed to the decrease of vacancy defects, dislocations, grain boundaries and Zr solutes.