The brazing of diamond is a promising way to fabricate grinding wheels for efficient machining and precision grinding.This work investigated the feasibility of bonding diamond grits onto Aluminium Alloy 7075(AA7075)su...The brazing of diamond is a promising way to fabricate grinding wheels for efficient machining and precision grinding.This work investigated the feasibility of bonding diamond grits onto Aluminium Alloy 7075(AA7075)substrate with a Ag–Cu–Ti filler alloy via laser fusion brazing.The interfacial microstructures and the strength of the brazed diamond joints were studied.The cross-section of the brazed diamond joint consists of a molten filler alloy layer,a molten pool,a heat effect zone,a columnar crystal zone and an equiaxed crystal zone.Within the interface of the filler alloy/substrate metal,microstructures observed possibly were Ag(s.s),Al(s.s),Tix Al,Al2 Cu and Mg intermetallic compounds.A layer of Ti C with a thickness of about 30–50 nm was found at the bonding interface of the diamond/filler alloy.The averaged peak shear force of the brazed joints was found to be approximately 39.8 N.The abrasion grinding test indicated that the diamond/AA7075 brazed joint was adequate for grinding.However,the pulled-off of grit was found to be the primary failure of this type of brazed joint.This work broadened the brazing diamond technique and the range of applications of brazed diamond wheels for efficient grinding.展开更多
基金Project(51204016)supported by the National Natural Science Foundation of ChinaProject(20120006120011)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China+1 种基金Project(FRF-TP-12-154A)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(11175020)supported by the National Science Foundation for Post-doctoral Scientists of China
文摘使用 Ag-Cu-Ti 合金粉、SiC 粉和 Zr 粉组成的混合粉末钎料,真空无压钎焊再结晶 SiC 陶瓷与 Ti 合金,观察 Zr 加入前后接头连接层组织结构的变化,研究了 Zr 的作用．结果表明,Zr 加入前,连接层主要由 Ag、SiC、Cu-Ti、Ti_3SiC_2、和 Ti-Si 相组成．Zr 加入后,连接层主要由 SiC、Ti_(1-x)C、Ti-Si、AgTi 和 AgCu_4Zr 相组成．Zr 的加入提高了连接层中 Ti 的活度,使 SiC 颗粒表面反应层 Ti_3SiC_2转变,生成了 Ti_(1-x)C 和 Ti-Si 相；提高了 Ti 与 SiC 颗粒的反应速度,使 SiC 颗粒减少；促进 Ti 与 Ag 的反应,生成了 AgTi．Zr 的加入导致连接层流动性的改善、连接层与 SiC 陶瓷界面结合强度的提高和接头热应力的降低,适量 Zr 的加入使接头剪切强度明显提高(达23．6MPa)．
基金National Natural Science Foundation of China(Nos.51975221,U1805251 and 51575198)。
文摘The brazing of diamond is a promising way to fabricate grinding wheels for efficient machining and precision grinding.This work investigated the feasibility of bonding diamond grits onto Aluminium Alloy 7075(AA7075)substrate with a Ag–Cu–Ti filler alloy via laser fusion brazing.The interfacial microstructures and the strength of the brazed diamond joints were studied.The cross-section of the brazed diamond joint consists of a molten filler alloy layer,a molten pool,a heat effect zone,a columnar crystal zone and an equiaxed crystal zone.Within the interface of the filler alloy/substrate metal,microstructures observed possibly were Ag(s.s),Al(s.s),Tix Al,Al2 Cu and Mg intermetallic compounds.A layer of Ti C with a thickness of about 30–50 nm was found at the bonding interface of the diamond/filler alloy.The averaged peak shear force of the brazed joints was found to be approximately 39.8 N.The abrasion grinding test indicated that the diamond/AA7075 brazed joint was adequate for grinding.However,the pulled-off of grit was found to be the primary failure of this type of brazed joint.This work broadened the brazing diamond technique and the range of applications of brazed diamond wheels for efficient grinding.
