钴基软磁非晶合金的巨磁阻抗效应研究进展

介绍了钴基软磁非晶合金丝与薄带的制备方法,重点讨论了频率、磁各向异性等因素对巨磁阻抗效应的影响.对非晶合金的巨磁阻抗效应传感器的应用进行了展望.     

Fe、P对C194铜合金组织与性能的影响

为探究国内某铜厂C194产品综合性能较低缘由,利用直流低电阻测试仪、电子万能试验机、发射光谱仪、扫描电镜及能谱仪等,对国内外C194产品的成分及性能进行了对比研究。试验结果表明,国内外C194产品析出相至少有两种,单质Fe肯定存在,且主要以单质存在,国外产品中P基本存在析出相中,国内产品中P除存在析出相中外,基体中也存在,此外,国内产品显微组织存在析出相尺寸粗大且分布不均,可见大尺寸洞隙等显微缺陷。后两者导致国内C194性能偏低。建议严格控制P的含量,改进固溶、时效、形变等处理工艺,以提高产品综合性能。     

引线框架用铜合金C194的制备与性能研究

采用形变热处理工艺制备了引线框架用铜合金C194,利用直流低电阻测试仪、维氏硬度计、金相显微镜和扫描电镜等研究了形变热处理工艺中时效温度和时间、二次时效间的冷轧形变率尤其是最终精轧率对热轧态C194性能和组织的影响.结果表明:形变热处理工艺为时效前预先冷轧37.5%、二次时效(500℃×2 h+500℃×2 h)、一次时效后以50%形变率冷轧,二次时效后终轧形变率为60%,轧制路线为1.6mm→1.0mm→0.5 mm→0.2 mm时,试样获得最佳综合性能,导电率为78%IACS,强度为550 MPa,硬度为158.9 HV,且具有良好的抗高温软化性能.     

Effect of rare earth alloying on creep rupture of economical 21Cr-11Ni-N heat-resistant austenitic steel at 650 ℃

The effect of rare earth(RE) on creep rupture of economical 21Cr-11Ni-N heat-resistant austenitic steel was investigated at 650 °C under different stress levels. It was found that RE could increase the time to creep rupture, especially at long-term creep duration. The logarithm of the time to creep rupture(lgtr) was a linear function of the applied stress(σ). RE addition was favorable to generating a high fraction of low-coincidence site lattice(CSL) boundaries which was a possible cause for improving the creep rupture resistance. The fracture surface of RE-added steel exhibited less intergranular cracks suggesting the alteration on the nature of grain boundaries due to the presence of RE. RE addition changed the morphology of the intergranular chromium carbides from continuous network shape to fragmentary distribution which was another cause for longer creep duration. These results strongly suggested that the effect of RE alloying played a crucial role in improving the creep rupture resistance.