稀土金属Y对Cu-Cr合金硬度和导电率的影响

研究了稀土金属Y不同添加量和不同固溶时效处理工艺对Cu0．8Cr合金硬度和导电率的影响。结果表明，铸态Cu0．8Cr合金的硬度随Y含量的增加而升高；经过不同固溶时效后，硬度出现波动，其中Cu0．8Cr0．4Y可获得最高硬度。过量的Y能增加硬度，但会降低导电率，经固溶时效处理后导电率最高的合金为Cu0．8Cr0．1Y。     

稀土Al-Mg-Si合金导线的热处理与性能研究

采用稀土微合金化和热处理相结合的方法制备出了高强高导电率的铝合金导线,研究了均匀化退火温度和时间、时效温度和时间对合金显微组织、力学性能和导电性能的影响,优化了均匀化退火和时效热处理工艺。结果表明:相对于铸态合金,均匀化退火态合金的硬度降低而导电率提高;随着均匀化退火温度的升高和均匀化退火时间的延长,合金的显微硬度逐渐降低而导电率不断提高,适宜的均匀化退火工艺为570℃/8 h;随着时效温度的提高,导电率达到标准所需的时间缩短,而抗拉强度达到标准的时间先增加而后减小;稀土铝合金导线适宜的时效热处理工艺为190℃/9 h,此时铝合金导线的抗拉强度为242 MPa、导电率为60.2%IACS。     

时效处理对CuMoCr合金硬度及导电率的影响

测试了时效处理前后CuMoCr合金的硬度及导电率,探讨了时效处理对CuMoCr合金硬度及导电率的影响。结果表明:时效处理能改变CuMoCr合金的硬度和导电率,当该合金经500℃保温4h时效后可获得较高硬度和导电率,其值分别为227HV和24.6 MS/m。     

高压处理对CuCrSeTeFe合金硬度和导电率的影响

通过测试导电率和硬度,分析了高压处理对CuCrSeTeFe合金硬度和导电率的影响.结果表明,高压处理能提高合金的硬度,但降低合金的电导率.当高压处理后再经500℃时效2h,合金的导电率明显提高,且压力越高,效果越明显.     

微量Ce对Cu-Cr-Zr合金性能影响

本文研究了稀土Ce对电气化铁路用高强高导接触线Cu-Cr-Zr合金的强度、硬度、导电性和热强性等的影响.结果表明微量稀土元素Ce的加入可以提高Cu-Cr-Zr合金的强度、硬度和耐热性,抗拉强度可达637 MPa,导电率为82.16%IACS,相对于Cu-Cr-Zr合金强度提高了56 MPa,而导电性略有降低.     

Cu-Cr-Zr-Ce合金时效特性的研究

研究了时效参数和变形量对Cu-0.35Cr-0.038Zr-0.055Ce合金性能的影响。结果表明:合金经920℃×1h固溶后,在500℃时效2h可获得较高的导电率和硬度;时效前对合金加以冷变形可加速第二相的析出,如合金经60%变形后在500℃时效0.5h时,导电率可达69.0%IACS,显微硬度达152.8HV,而固溶后直接时效导电率仅为56.3%I-ACS,显微硬度为130HV;微量稀土元素Ce的加入,使合金的显微硬度提高了18～25HV,而导电率略有降低。     

镁与热处理对Al-4Si-(xMg)合金导电性及力学性能的影响

利用SEM、XRD、EDS、硬度计及电阻率测试仪等方法分析Mg元素和不同热处理对Al-4Si-(xMg)(x=0~1.5%,质量分数)系列合金导电率及硬度的影响。结果表明:随Mg添加量增加,铸态合金的导电率和硬度先增后减,最佳添加量为1.1%。Mg使铸态合金硬度显著增加,但恶化了其导电率。Al-4Si-(xMg) 合金经不同热处理后,合金导电率大幅提高,硬度略有降低。其中,固溶时效对合金导电率的提高最显著,硬度降低幅度最小,使Al-4Si-1.1Mg合金导电率和硬度匹配关系最好。通过Mg元素和固溶时效的协同作用,可使铸态Al-4Si合金导电率由43.3%IACS提高至50.9%IACS,硬度由41.5 HV0.5增加至84.3 HV0.5。     

Cu-Ag-Cr合金时效析出行为研究

研究了时效参数和变形量对Cu-0.1Ag-0.61Cr合金性能的影响。结果表明:合金经980℃×20 min固溶后,在480℃时效1 h可获得较高的导电率和硬度。时效前对合金加以冷变形可以显著提高其显微硬度,合金经60%变形后在480℃时效30 min时,峰值硬度可达165.13 HV,导电率可达83%IACS,而固溶后直接时效分别仅为153.46 HV和77.63%IACS。与Cu-0.1Ag-0.46Cr合金相比其显微硬度有较大提高而导电率降低很少。     

热处理工艺对Cu-Ag-Cr合金性能的影响

研究了不同固溶温度、时效参数和变形量对Cu-0.1Ag-0.61Cr合金性能的影响.结果表明合金显微硬度随固溶温度升高而降低,导电率反而升高.合金经980℃×20 min固溶后,在480℃时效1 h可获得较高的导电率和硬度.时效前对合金加以冷变形可以显著提高其显微硬度,合金经60%变形后在480℃时效30 min时,可获得良好的综合性能.     

Fe对稀土电工铝导线性能的影响

探究了Fe元素对稀土电工铝导线性能的影响,测试了合金的抗拉强度、伸长率及导电率。研究结果表明,Fe元素能够显著提高铝导线的抗拉强度和伸长率,但随Fe元素含量增高,其对铝导线导电率的降低作用越明显。综合抗拉强度、伸长率及导电率的检测结果,W（Fe）=0．3％时,合金的力学性能和导电性能较好。     

时效温度和Cr含量对Cu-Ag-Cr合金性能的影响

研究了时效温度和Cr含量对70%冷轧变形的Cu-Ag-xCr合金的硬度、导电性能和耐蚀性能的影响。结果表明,Cu-Ag-xCr合金在450~500℃时效后,其硬度随时效温度增加而降低,随Cr含量增加而升高;时效温度和Cr含量对合金电导率的影响不大;随时效温度升高,合金耐蚀性降低;随Cr含量增加,腐蚀速率降低,耐蚀性提高。Cr含量为0.34%时,在450℃时效2h后,其综合性能较好,电导率为47.02 MS/m,硬度(HV0.1)达到128.34,耐腐蚀性较好。     

热处理对粉末冶金Cu-15Ni-8Sn合金组织与性能的影响

以Cu-15Ni-8Sn合金粉为原料制备了粉末冶金试样,研究其在不同的固溶温度、冷压变形、时效温度和时效时间条件下的硬度,着重研究了840℃×15 min固溶+40%冷压变形条件下时效温度和时间对硬度及剪切强度的影响规律,采用金相及扫描电镜分析了相应的微观组织。结果表明,影响Cu-15Ni-8Sn合金硬度的主次因素为:冷压变形量>时效时间>时效温度>固溶温度,较优的工艺参数为840℃×15 min固溶+40%冷压变形+400℃×4 h时效,可获得37.6～38.3 HRC的高硬度和570～628 MPa的抗剪切强度。     

时效制度对7475铝合金组织与性能的影响

通过对不同时效制度下的常温拉伸性能、硬度、电导率、抗应力腐蚀性能、断裂韧性等性能测试及微观组织观察,分析不同时效制度对7475铝合金挤压型材的微观组织与性能影响。结果表明,单级峰值时效（T6）具有很高的强度,但抗应力腐蚀性能较差,主要是因为晶界析出物的性质所决定的;双极时效（T76、T73）由于晶界析出物呈粗大和弧立状分布,具有较好的抗应力腐蚀性能,但由于过时效晶内析出相尺寸增大,强度有较大程度的下降。同时实验表明,时效制度对7475挤压型材断裂韧性的影响并不大。     

预拉伸处理对2024铝合金组织和性能影响

采用硬度测试、室温力学性能测试、组织观测,研究了自然时效前的预拉伸(预拉伸率1%、1.5%,2%、2.5%、3%)对2024铝合金时效过程和拉伸性能影响。结果表明,预拉伸处理延缓了合金的自然时效过程,但提高了合金的硬度和强度。当预拉伸率为2%时,合金的最高强度和伸长率分别为456 N/mm2,20.6%,这是由于冷变形量不同、回复所引起的软化、GPB区和S″相强化综合作用所导致的。自然时效时,析出物为GPB区、T相(Al20Cu2Mn3)及S″相(Al2CuMg),其中GPB区、S″(Al2CuMg)相为主要强化相,T相(Al20Cu2Mn3)有细化晶粒的作用,比未预拉伸处理合金的析出相数量多,且析出相分布更均匀,使合金厚板的强度提高。     

Ageing behavior of Cu-15Ni-8Sn alloy prepared by mechanical alloying

1INTRODUCTIONCu-Ni-Snal1oyshavebeenconsideredaspossiblesubstitutesforCu-Bealloysinthemanu-factureofc0nnectors,springcomponentsandsoforth,intheelectronicsindustriesbecauseoftheiroutstandingpropertiessuchashighstrength,highelasticmodulus,exce1lenterosi0nresistanceandhighresistancetostressrelaxationatelevatedtemperature['].Inaddition,com-paredwithCu'Bealloys,thelowcostandminorpollutioninthepreparationprocessofthealloyhavealsoattractedtheincreasingattentionofmanyresearchers.However,extensiv…     

Effect of ageing on microstructure and mechanical properties of bulk, cryorolled, and room temperature rolled Al 7075 alloy

The effect of ageing on mechanical properties and microstructural characteristics of a precipitation hardenable Al 7075 alloy subjected to rolling at liquid nitrogen temperature and room temperature are has been investigated in the present work employing hardness measurements, tensile test, XRD, DSC, and TEM. The solution-treated bulk Al 7075 alloy was subjected to cryorolling and room temperature rolling to refine grain structures and subsequently ageing treatment to simultaneously improve the strength and ductility. The solution treatment combined with cryorolling up to a true rolling strain of 2.3 followed by low temperature ageing at 100 °C for 45 h has been found to be the optimum processing condition to obtain fine grained microstructure with improved tensile strength (642 MPa) and good tensile ductility (9.5%) in the Al 7075 alloy. The combined effect of suppression of dynamic recovery, partial grain refinement, partial recovery, solid solution strengthening, dislocation hardening, and precipitation hardening are responsible for the significant improvement strength-ductility combination in the cryorolled Al 7075 alloy subjected to peak ageing treatment. The cryorolled and room temperature rolled Al 7075 alloy, upon subjecting to peak ageing treatment, have shown higher strength and ductility in the former than the latter. It is due to presence of high density of nanosized precipitates in the peak aged cryorolled sample.     

一种新型Al-Zn-Mg-Cu高强铝合金的析出行为及性能(英文)

对一种新型高强Al-Zn-Mg-Cu合金在单级时效过程中的硬度、强度、电导率变化及相应的析出行为进行系统的研究。结果表明,电导率随着时效温度的升高和时效时间的延长而不断增高。在时效开始阶段,硬度和强度随着时效的进行迅速升高并达到峰值。在120°C时效时,硬度和强度到达峰值后保持稳定,主要的析出相是GPI区、GPII区和η′相。在120°C长时间(直至24h)时效后,GPI区和GPII区仍能稳定存在。在160°C时效时,硬度和强度到达峰值后迅速下降。与120°C时效相比,在160°C时效时,析出过程更快。在160°C时效1h后,未观察到GPI区及GPII区的存在,主要的析出相为η′相。在160°C时效24h后,主要的析出相为η相。     

Evolution of microstructure and hardness of AE42 alloy after heat treatments

The AE42 magnesium alloy was developed for high pressure die casting (HPDC) from low-aluminum magnesium alloys. In this alloy the rare earth (RE) elements were shown to increase creep resistance by forming Al_xRE_y intermetallics along the grain boundaries. The present work investigates the microstructure of squeeze cast AE42 magnesium alloy and evaluates its hardness before and after heat treatments. The change in hardness is discussed based on the microstructural observations. Some suggestions are given concerning future design of alloy compositions in order to improve high temperature creep properties even further. It is shown that the microstructure of the squeeze-cast AE42 alloy is stable at high temperature 450 °C. The subsequent solution and ageing treatments have a limited effect on the hardness. The weak age-hardening is attributed to the precipitation of small amount of Mg₁₇Al₁₂-phase with the use of about 0.7 wt.% aluminum. The heat treatment to achieve a maximum increase in the hardness is: solution treatment at 450 °C for 5–10 h followed by an ageing treatment at 190–220 °C for about 5 h.     

时效制度对Al-Cu-Mg-Ag-Zr合金组织和性能的影响

采用硬度、电导率、拉伸性能、撕裂性能等性能测试和差示扫描量热(DSC)、透射电镜(TEM)等分析方法研究单级时效和多级断续时效对高Cu/Mg比Al-Cu-Mg-Ag-Zr合金组织和性能的影响.结果表明与T6态合金相比,多级断续时效处理在保持合金强度、硬度和电导率同时,显著提高合金的断裂韧性;160℃单级时效过程中,Ω和θ′相同时析出;断续时效第一级和第三级时效的主要析出相与单级时效的类似,第二级低温时效过程中,θ′相明显析出,未出现明显的Ω相析出特征.     

The influence of silicon content on microstructure and hardness of Mo-Si alloys

Mo-Si alloy sheets with different silicon content were fabricated by powder-metallurgical and thermo-mechanically processing. The effect of Si content and annealing temperature on microstructure and hardness of the Mo-Si alloys were studied by using optical microscopy (OM), transmission electron microscopy (TEM) and Vickers hardness tester, respectively. The results indicated that the presence of Si can effectively refine the grain sizes and improve the hardness of Mo-Si alloys. Si can also increase the recrystallization temperature of alloys and play a significant role in restraining the grain growth at high temperatures. Increasing the annealing temperature, the microstructure of Mo-Si alloy sheets is gradually coarsened and changed from fibrous to equiaxed structure, causing reduction in hardness. The hardening effect in the Mo-Si alloys came from the refined grain strengthening, solid solution strengthening, and second phase particle strengthening, which are closely dependent on the Si content and annealing temperature.