钎焊温度对TC4钛合金真空钎焊接头组织及性能影响研究

Study on the effect of brazing temperature on the organisation and properties of TC4 titanium alloy vacuum brazing Joints Organisation and Properties

通过自行设计、制备的Ti-38Zr-24Ni(wt.%)钎料真空钎焊TC4钛合金,在改变钎焊温度(900~990℃)条件下,对钎焊接头的组织及性能进行了研究。钎焊接头由三个区组成:扩散区、界面区和中心区。Ni和Zr原子扩散进入母材引起β-Ti转变形成扩散区,扩散区为共析组织α-Ti和(Ti,Zr)_(2)Ni和剩余母材基体组成;界面区为层片状α-Ti和(Ti,Zr)_(2)Ni共析组织组成;中心区为大块状(Ti,Zr)_(2)Ni金属间脆性化合物和尺寸大小不一的层片状α-Ti+(Ti,Zr)_(2)Ni组织组成。提高钎焊温度,扩散区和界面区的宽度增加,中心区的宽度降低,且钎缝中心IMC化合物的数量降低。采用钎焊温度990℃时获得最高抗剪强度,其值为647MPa。

The organisation and properties of brazed joints were investigated by vacuum brazing TC4 titanium alloy with Ti-38Zr-24Ni(wt.%)brazing material designed and prepared by ourselves,and the brazed joints were investigated under the condition of changing the brazing temperature(900~990℃).The brazed joints were composed of three zones:diffusion zone,interface zone and centre zone.the diffusion zone was formed by the diffusion of Ni and Zr atoms into the base material causingβ-Ti transformation,and the diffusion zone was composed of the eutectic tissues ofα-Ti and(Ti,Zr)_(2)Ni and the remaining base material;the in-terface zone was composed of the laminarα-Ti and(Ti,Zr)_(2)Ni eutectic tissues;and the centre zone was composed of the bulk(Ti,Zr)_(2)Ni.The central zone is composed of large(Ti,Zr)_(2)Ni and intermetallic brittle compounds and laminarα-Ti+(Ti,Zr)_(2)Ni tissues of different sizes.Increasing the brazing temperature in-creased the width of the diffusion and interfacial zones,decreased the width of the central zone,and de-creased the amount of IMC compounds in the centre of the braze seam.The highest shear strength was ob-tained using a brazing temperature of 990°C with a value of 647 MPa.