TiB_w/TC4钛合金与C/C复合材料钎焊接头的界面组织结构

采用活性钎料TiZrNiCu对TiBw/TC4钛合金和C/C复合材料进行了钎焊连接,借助SEM,EDS,XRD等分析手段研究了钎焊工艺参数对接头界面组织结构的影响.结果表明,采用TiZrNiCu钎料可以实现对两种材料的连接,接头典型的界面结构为:C/C复合材料/TiC+(Ti,Zr)2(Cu,Ni)/Ti(s,s)+(Ti,Zr)2(Cu,Ni)/TiBw/TC4钛合金.随着连接温度的升高或保温时间的延长,钎焊接头界面生成产物的种类并没有发生改变,但C/C复合材料侧TiC反应层逐渐变得连续且厚度逐步增加,α-Ti枝状晶变得粗大且数量增多,Ti(s,s)+(Ti,Zr)2(Cu,Ni)层逐渐变宽,(Ti,Zr)2(Cu,Ni)逐步分散在Ti(s,s)中.

Brazing of TiB_w/TC4 composite and Ti60 alloy using TiZrNiCu amorphous filler alloy

TiBw/TC4composite was brazed to Ti60alloy successfully using TiZrNiCu amorphous filler alloy,and the interfacialmicrostructures and mechanical properties were characterized by SEM,EDX,XRD and universal tensile testing machine.The typicalinterfacial microstructure was TiBw/TC4composite/β-Ti+TiB whiskers/(Ti,Zr)2(Ni,Cu)intermetallic layer/β-Ti/Ti60alloy whenbeing brazed at940°C for10min.The interfacial microstructure evolution was influenced strongly by the diffusion and reactionbetween molten fillers and the substrates.Increasing brazing temperature decreased the thickness of brittle(Ti,Zr)2(Ni,Cu)intermetallic layer,which disappeared finally when the brazing temperature exceeded1020°C.Fracture analyses indicated thatcracks were initialized in the brittle intermetallic layer when(Ti,Zr)2(Ni,Cu)phase existed in the brazing seam.The maximumaverage shear strength of joints reached368.6MPa when brazing was conducted at1020°C.Further increasing brazing temperatureto1060°C,the shear strength was decreased due to the formation of coarse lamellar(α+β)-Ti structure.

TiZrNiCu-B/Ti60润湿性及其与TiBw-TC4钎焊研究（英文）

采用座滴法在真空下研究了硼含量对TiZrNiCu/Ti60润湿性的影响,且在940℃保温10 min条件下实现了其与TiBw-TC4的钎焊。通过SEM、XRD以及剪切实验研究了界面显微组织及剪切力学性能。结果表明,添加B元素可以与Ti原位合成TiBw,从而细化界面的显微组织。当B质量分数为0.3%时,TiBw-TC4/TiZrNiCu-B/Ti60接头的最大抗剪切强度为177 MPa,比无B的接头强度高65%。然而,过量的B含量使TiZrNiCu-B在Ti60合金基体上产生大量的TiBw,导致润湿性恶化,在钎焊接头形成微孔和未焊合区域,从而使抗剪切强度下降。

低频扭转振动辅助螺旋铣孔切削力模型研究

晶须增强钛基复合材料因其高比刚度、比强度等优异性能,被广泛用于航空航天、车辆运输以及新能源等领域;然而,由于材料各向异性,在常规制孔加工中极易产生缺陷,限制了其大量推广和应用。为此,结合低频扭转振动的运动特点和螺旋铣削的加工特点,提出低频扭转振动辅助螺旋铣孔(低频扭振螺旋铣孔)工艺方法,并进一步推导了其切削力模型;在此基础上,开展了TiBw/TC4复合材料的铣孔实验研究,验证了切削力模型的合理性。仿真分析表明,扭振切向进给与切向每齿进给相同,扭振频率与切削频率同频时,端面合力的平均切削力峰值较常规螺旋铣孔分别下降近13.05%和13.64%。实验研究表明,低频扭振螺旋铣孔有助于减少出/入口毛刺、孔壁划痕、破碎等缺陷,并可有效降低刀具磨损;相较于常规螺旋铣孔,孔壁粗糙度降低36.29%。