TiAl合金与GH3039摩擦焊接界面组织

Intermediate Phases of TiAl/GH3039 Friction Welding Joint

使用GH3039合金作为γ-TiAl与碳钢摩擦焊接的过渡第三体,采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析了TiAl/GH3039摩擦焊接接头的界面结构。结果表明,γ-TiAl和GH3039摩擦焊接接头的最大抗拉伸强度能达到400 MPa以上。GH3039一侧热力影响区的塑性变形大于TiAl一侧,并且在两侧均发生动态再结晶。接近GH3039母材相层中的Ni含量几乎不变,接近TiAl母材相层中的Ti含量也几乎不变。在GH3039侧面附近的焊接区中,富Ni和富Cr晶粒的分布是互补的。Ti和Al容易溶于富Ni的晶粒中,而Mn容易溶于富Cr的晶粒中。在结合区中形成的大量富Cr晶粒是体心立方结构的α-Cr。γ-TiAl和GH3039摩擦焊接的典型界面结构为:γ-TiAl+α_(2)-Ti_(3)Al/α_(2)+τ_(3)/τ_(3)-Al_(1+x−y)Ti_(1+y)Ni_(1−x)/τ_(3)+α-Cr/(Ni,Cr)_(ss)/GH3039。

GH3039 superalloy was used as the third body metal to weldγ-TiAl with carbon steel,and the interface structure of the TiAl/GH3039 friction welding joint was analyzed by scanning electron microscope(SEM)and transmission electron microscope(TEM).The results show that the maximum tensile strength of the weld joint is more than 400 MPa after friction welding ofγ-TiAl and GH3039 alloys.The plastic deformation of thermo-mechanically affected zone(TMAZ)on GH3039 side is larger than that on TiAl side,and dynamic recrystallization occurs on both sides.The Ni and Ti contents in the phase layer close to GH3039 and TiAl alloys hardly change,respectively.In the welding zone near GH3039 side,the distribution of Ni-rich and Cr-rich grains are complementary.Ti and Al are easily soluble in the Ni-rich crystal grains,and Mn is easily soluble in the Cr-rich crystal grains.A large number of Cr-rich grains formed in the bonding zone have body-centered cubic structure ofα-Cr.The interface microstructure of the friction welding zone betweenγ-TiAl and GH3039 alloys isγ-TiAl+α_(2)-Ti_(3)Al/α_(2)+τ_(3)/τ_(3)-Al_(1+x−y)Ti_(1+y)Ni_(1−x)/τ_(3)+α-Cr/(Ni,Cr)_(ss)/GH3039.