填丝TIG焊接Mo—Cu合金与18-8不锈钢接头的微观组织

采用填丝钨极氩弧焊（TIG）对Mo—Cu合金与18—8不锈钢进行焊接．采用金相显微镜、扫描电镜、显微硬度计及x射线衍射仪等对Mo—Cu／18—8接头的微观组织、显微硬度、元素分布及熔合区附近的物相组成进行分析．结果表明,Mo—Cu合金侧的熔合区为马氏体和奥氏体的混合组织,焊缝和18—8钢侧的熔合区为奥氏体和铁素体双相组...     

Mo-Cu合金与1Cr18Ni9Ti不锈钢真空钎焊接头的组织性能

采用Ag-Cu-Ti钎料,控制钎焊温度为910℃,保温时间为20 min,可以实现Mo-Cu合金与1Cr1 8Ni9Ti不锈钢的真空钎焊,接头抗剪强度为75 MPa.采用扫描电镜、能谱分析仪和显微硬度计对Mo-Cu/1 Cr18 Ni9Ti接头组织特征及性能进行分析.结果表明,钎焊接头靠近1Cr18Ni9Ti钢一侧,主要形成Ag-Cu共晶组织和少量的TiC相;靠近Mo-Cu合金一侧,Ag,Cu元素在合金与钎缝间相向扩散,共晶组织消失,以富铜相为主.钎缝的显微硬度明显低于Mo-Cu合金和1Cr18Ni9Ti不锈钢母材,无脆性化合物生成,剪切断口呈现剪切韧窝的形貌特征.     

汽车动力学稳定性控制系统关键技术研究

对汽车动力学稳定性的问题,从特点、功能、原理、结构、组成等方面进行了论述,并对其重要参数的获得方式进行了详细分析,通过建立汽车操纵稳定性控制系统,能够有效的提高车辆操作性能,进而提供车辆的稳定性和可靠性,确保人员和车辆的安全。     

钼及钼合金的焊接研究现状

钼及钼合金是一种极具应用前景的材料,但钼及钼合金对气体杂质污染敏感,呈现低温脆化、高温氧化的特点,焊接接头韧性、强度等性能较差。因此,国内外学者对其进行了研究。本文综述了钼及钼合金的焊接技术及工程应用,对钼及钼合金焊接中出现的问题进行了总结分析,指出改善接头韧性、防止裂纹和气孔的产生是实现钼及钼合金焊接的关键。     

Microstructure and fracture morphology of Mo－Cu/Cr18－Ni8 brazed joint in vacuum*

Mo-Cu composite and Cr18-Ni8 stainless steel were brazed with Ni-Cr-P filler metal in a vacuum of 10-4 Pa and a Mo-Cu/Cr18-Ni8 joint was obtained. Microstructure in Mo-Cu/Cr18-Ni8 joint was investigated by field-emission scanning electron microscope( FE-SEM) with energy dispersive spectrometer( EDS). Shear strength of Mo-Cu/Cr18-Ni8 lap joint was measured by electromechanical universal testing machine. An excellent Mo-Cu/Cr18-Ni8 joint with a shear strength of 155 MPa was achieved at 980 ℃ for 20 min. Brazed joint was mainly comprised of eutectic structure in the center of brazing seam,matrix structure and lump structure. Ni-Cu( Mo) and Ni-Fe solid solution were at the interface beside Mo-Cu composite and Cr18-Ni8 stainless steel,respectively. Shear fracture exhibited mixed ductile-brittle fracture feature with trans-granular fracture,ductile dimples and tearing edges. Fracture originated from the interface between brazing seam and Mo-Cu composite.