中间退火对形变Cu-15Cr-0．1Zr原位复合材料性能的影响

研究了采用中间退火＋冷变形方法制备的形变Cu-15Cr-0．1Zr原位复合材料的显微组织、抗拉强度和导电性。结果表明：铸态铬相为树枝晶,在变形过程中,铬相变成纤维状,横截面上呈卷曲薄片状;适当的中间退火能显著提高其电导率;配合适当的中间退火与冷变形,可以得到较好的强度和导电性;应变量为6．43时,采用450℃＋400℃或500℃＋500℃两次中间退火工艺制备的形变Cu-15Cr-0．1Zr原位复合材料具有较好的性能组合,分别为1227MPa／64．89／6IACS、1025MPa／71．5％IACS。     

扭转变形与退火处理对再生铜杆显微组织和性能的影响

对采用火法精炼高导电(FRHC)废杂铜精炼工艺+连铸连轧工艺制备的直径8 mm再生铜杆进行720℃扭转变形和500℃×60 min退火处理,研究了扭转变形和退火处理对其显微组织、力学性能和导电性能的影响。结果表明:在连铸连轧过程中再生铜杆组织中产生孪晶,扭转变形导致的孪晶交叉、孪晶与位错等的交互作用使得晶粒发生细化;扭转变形后再生铜杆的抗拉强度由未扭转变形的215 MPa提高到273 MPa,但断后伸长率由40%降低到21%,硬度增大,导电率由99.37%IACS降低至86.78%IACS;再进行退火处理后,再生铜杆组织形成尺寸更均匀的等轴晶,抗拉强度降至208 MPa,断后伸长率提高到55%,硬度降低,导电率增至98.21%IACS。     

内氧化法制备点焊电极用ZrO_2/Cu复合材料的组织与性能

采用改进的内氧化法制备了点焊电极用ZrO2/Cu复合材料,并对其进行了塑性变形及热处理,研究了不同工艺条件下复合材料的显微组织、硬度和导电性。结果表明:ZrO2/Cu复合材料组织均匀细小,ZrO2颗粒弥散分布于铜基体中;随着冷拉拔变形量增大,复合材料的硬度增大,导电率降低,其较佳的冷拉拔变形量为60%,此时复合材料的硬度可达100 HV,导电率为86%IACS;随着加热温度的提高和保温时间的延长,复合材料仍具有较高的导电率,且硬度变化较小,其耐高温性优于铜铬锆合金的,适合作为点焊电极材料。     

铜银锆合金热处理工艺的优化及析出相

对经不同热处理后铜银锆合金的性能进行了研究,通过透射电镜分析了合金中析出相的种类及形貌。结果表明:合金经920℃×40min固溶水淬+30%冷变形+420℃×3h时效空冷处理后,能获得较好的力学性能与电学性能,硬度为123HB,电导率为88.8%IACS,室温抗拉强度为430MPa,断后伸长率为13.5%,断面收缩率为45.2%;热处理后合金基体上弥散分布着Cu5Zr析出相和粗大的铜银锆饱和固溶体。     

铸态Cu-5.7%Cr合金在等径角挤压中铬纤维的原位形成

利用等径角挤压(ECAP)技术对铸态Cu-5.7%Cr合金进行了变形,对变形过程中原位铬纤维的形成进行了研究;根据纤维的形成过程,分析了Segal和Mcnelly剪切变形模型的适用性.结果表明:在挤压变形过程中,树枝状的铬相发生了旋转和延伸,从而形成细长的原位纤维,随着变形量的增大,纤维方向趋于与x轴平行;考虑摩擦的影响,提出了用修正的Mcnelly剪切变形模型来计算形变原位纤维的倾斜角,计算值与试验结果吻合较好.     

快速凝固Al—Cr—Zr合金的显微组织

利用单辊熔体喷射快速凝固技术制备了高温使用的Al-4Cr-4Zr(原子百分比）合金,用透射电子显微镜观察了合金的显微组织,结果表明;快凝合金急冷态组织为过饱和α-Al固溶体和Al13Cr2相,而在300℃退火4h后,很细小的Al3Zr相从α-Al中析出。     

关于铜铬合金的细化实验研究

利用形变 热处理的工艺路线，即把铜铬合金试样用压力机及轧机进行一定的变形，然后在1073K左右进行真空退火，来探讨铜铬合金组织中铬粒子细化问题。实验结果表明，由粉末冶金法制备的铜铬合金塑性很好，当铜铬合金的冷变形率达到一定程度时，铬粒子会随铜基体发生塑性变形，在本实验条件下，虽然铬粒子未明显细化，但铬这一很脆的金属在合金中可以形变这一现象表明，形变 热处理细化铬粒子是可行的。     

Cu-Al_2O_3复合材料的塑性变形与再结晶

研究了弥散强化型 Cu- Al2 O3 复合材料的塑性变形行为 ,以及塑性变形和退火对材料组织与性能的影响规律。结果表明 :复合材料的冷变形组织以孔隙的充分压合、纤维状长晶和界面Al2 O3 的均匀分布为特征 ,冷变形后材料的性能大大提高。稳定的 Al2 O3 粒子可显著提高复合材料的再结晶温度 ,高温退火与热变形均未发生明显的再结晶。复合材料具有优良的抗热稳定性和很高的高温强度。     

双重退火与变形水冷工艺对TC11钛合金组织和性能的影响

研究了双重退火及变形水冷处理工艺对TC 11钛合金组织、性能的影响,指出合适的变形水冷工艺可使合金的室温位伸、500℃拉伸、500℃/100 b热暴露及疲劳极限达到双重退火的水平。并指出在500℃/588 MPa 持久拉伸条件下,由于相界的空洞聚集及晶内局部应变,可使经变形水冷后矫正并时效的合金断裂抗力下降。     

铸锭枝晶间距和冷变形量对Cu-15Ni-8Sn合金显微组织和硬度的影响

采用中频感应炉与高频感应炉制备了枝晶间距分别为11,18,23,50μm的Cu-15Ni-8Sn合金铸锭,并依次进行了均匀化退火处理、固溶处理、冷变形和时效处理,研究了铸锭枝晶间距和冷变形量对合金显微组织和硬度的影响。结果表明:试验合金铸锭的显微组织均为明显的树枝状组织;经均匀化退火及固溶处理后,铸锭枝晶间距越小的合金组织也越趋于均匀;冷变形量越大,合金中的晶粒变形越严重,且经400℃时效后合金中的黑色不连续脱溶产物越早析出,时效硬度峰也越早出现;在相同的冷变形量下,铸锭枝晶间距越小的合金中黑色不连续脱溶产物越晚析出,且时效硬度峰越晚出现。     

铜铬合金的冷变形及断丝原因分析

实验研究了拉拔变形程度与亚微米晶铜铬合金显微组织、力学性能和导电性能的关系,并分析了拉拔过程中断丝的原因.结果表明,亚微米晶铜铬合金通过拉拔变形获得的变形晶粒尺寸为200 nm,硬度可达HV 185,抗拉强度达到600 MPa以上,而导电性能稍有下降.丝材断口形貌为杯锥断口,属典型的微孔聚集型断裂.在拉拔过程中,丝材中存在的大量细小弥散的第二相Cr颗粒与Cu基体变形不协调,是微孔产生和裂纹扩展的主要原因.     

Effect of cold compression on precipitation and conductivityof an Al–Li–Cu alloy

Transmission electron microscopy has been used to investigate the effect of increasing the degree of deformation applied by cold compression on the ageing kinetics and electrical conductivity response of an Al–Li–Cu alloy containing Mg and Ag. When cold compressed greater than 3%, the increased dislocation density accelerates the widespread precipitation of the T₁ phase resulting in an enhanced age hardening response. The lengthening rate of T₁ precipitates is also reduced in this cold compressed condition owing to the reduced local solute supersaturation, a result of the widespread precipitation of T₁ plates. Cold compression by less than 3% does not increase the age hardening response, and the precipitation of GP zones/θ″ appears to be suppressed. Precipitation of the T₁ phase is also not significantly enhanced compared with that of the more than 3% cold compressed conditions. The anomalous decrease in electrical conductivity is associated with the nucleation and growth of the T₁ phase. Strain fields around T₁ precipitates combined with the increased volume fraction of T₁ are thought to be the cause of the anomalous conductivity behaviour.     

双相不锈钢导电性能研究

研究了Si、Al元素及不同回火温度对高强度双相不锈钢导电性能的影响,结果表明,Si、Al元素是影响合金导电性能的主要因素,加入少量的Si、Al元素可大幅度提高合金材料的电阻率;热处理对电阻率的影响,是由热处理带来的多方面因素所决定的,回火温度对电阻率的影响并不大,同一成分不同回火温度所得合金的电阻率变化在5%以内。     

十字轴式万向联轴器相位差对传动平稳性影响研究

针对某钢厂冷轧线电气调试时要求的传动系统转速波动问题,分析了万向联轴器中间轴两端叉头相位差对传动平稳性的影响,给出了制造允许的相位差范围。研究结果表明:中间轴两端叉头相位差和万向联轴器工作角度越大,传动系统的转速波动越大,且波动频率是旋转频率的2倍。     

变形及退火处理对铜合金丝材性能的影响

文中研究了拉拔变形及退火处理对铜合金显微组织、力学性能和导电性能的影响,并进行了强化机理分析.结果表明,处理后材料具有较高的强度和良好的导电性能.冷变形和退火处理促进了材料中第二相粒子的析出;合金组织细小均匀,兼有细晶强化、弥散强化和形变强化的效果.     

Fe78Si9B13非晶薄带的巨磁阻抗效应

采用4284A型阻抗分析仪研究了退火处理、非晶薄带长度、交流电频率和磁场强度等对Fe<,78>Si<,9>B<,13>非晶薄带巨磁阻抗效应的影响.结果表明:退火可以提高非晶薄带的阻抗变化幅度;其阻抗随着薄带长度的增加和交流电频率的升高而增大,随着磁场强度的增大而减小;其阻抗变化幅度随着薄带长度的增加和交流电频率的升高和...     

Evaluation of surface roughness and nanostructure of indium tin oxide (ITO) films by atomic force microscopy

Indium tin oxide was deposited on a glass (soda lime glass) by radiofrequency sputtering system at different sputtering gas (argon/oxygen 90/10%) pressures (20-34 mTorr) at room temperature. The sputtering rate was affected by the sputtering gas pressure. The optimum sputtering gas pressure was found to be 27 mTorr. The samples at different thicknesses (168, 300, 400, 425, 475, 500 and 630 nm) were deposited on the substrate. Transparency, electrical conductivity and surface roughness of the films were characterized. The samples were annealed at 350, 400 and 450 degrees C to evaluate annealing process effects on the concerned parameters and, therefore, the above-mentioned measurements were repeated again. The films exhibited reasonable optical transmittance and electrical conductivity and greatly improved after annealing. The characterization was focused on the scanning of the film surfaces before and after annealing, which has a prominent effect on the optical properties of the films. Film surfaces were scanned by scanning probe microscopy in contact atomic force mode. The most consideration was devoted to image analysis.     

Sliding wear behavior of copper alloy contact wire against copper-based strip for high-speed electrified railways

This paper reports the study of the sliding wear behavior of the Cu–Ag–Cr wire. Cu–Ag–Cr alloy is a promising contact wire material for high-speed electrified railways, which has an excellent combination of mechanical strength and electrical conductivity. Wear tests were conducted under laboratory with a special sliding wear apparatus, which simulated the tribological conditions of sliding current collectors on overhead wires in the railway system. The Cu–Ag–Cr alloy wire was slid against a copper-based powder metallurgy strip under unlubricated conditions. The same strip as those in the train systems were used. Worn surfaces of the Cu–Ag–Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum (EDS). Within the studied range of electrical current, normal pressure and sliding speed, the wear rate increased with the increasing electrical current and the sliding distance. Compared with a Cu–Ag contact wire under the same conditions, the Cu–Ag–Cr alloy wire had much better wear resistance. Adhesive wear, abrasive wear and arc erosion were the dominant mechanisms during the electrical sliding processes.     

激光处理冷轧Q235/40Cr干摩擦试验研究

采用CO2横流式激光器对Q235/40Cr材料进行表面强化处理。使用S-360型扫描电镜观察激光硬化区金相组织及成分并观察表面磨损形貌,采用CHX-1超显微硬度计测量激光强化区断面的显微硬度。通过40Cr与冷轧Q235配副进行干摩擦试验,结果表明,与淬火40Cr配副的Q235的平均磨损速率最小,而与1400 W激光功率处理40Cr配副的Q235的平均磨损速率最大,淬火的40Cr平均磨损速率是激光处理的2~3倍。40Cr磨损为磨粒磨损并有微裂纹产生,Q235以磨粒磨损为主,表面产生较深的犁沟。经激光硬化处理后40Cr的耐磨性要优于正常淬火40Cr的耐磨性。