TiAl基合金固态焊接

SOLID-STATE JOINING OF TiAl BASED ALLOYS

研究了各种显微组织TiAl基合金材料之间自体固态焊接实验结果表明，粗晶TiAl基合金与粗晶TiAl基合金作焊接对偶件时，在结合面上形成与基体组织不同的再结晶细晶组织.这种显微组织的差异及结合面上微孔隙的残存，导致焊接组构件的断裂主要发生在结合面上.如采用粗晶TiAl合金与细晶双态组织TiAl基合金对焊时，由于细晶TiAl基合金具有较好超塑性变形能力、在热压力作用下此部分材料可镶嵌入焊接对偶另一侧，得到较好的结合采用细晶TiAl基合金材料作对偶进行固态焊接时，由于对偶材料都具有良好的超塑性，因此，可以仅仅通过晶界滑移进行超塑性变形，得到完全结合的焊接界面，结合面上的显微组织与基体一致、焊接对偶件材料得到高的室温力学性能，其值高达σb＝533MPa；δ≈2%;此时，所有的拉伸试样的断裂都发生在非结合面上.

Solid-state joining between TiAl based alloy samples with various microstructures was investigated. When joining between coarse-grained TiAl based alloys, a fine recrystallized microstructure, which was different from those of the substrates, formed in the joining interface. When joining between a coarse-grained TiAl based alloy and an alloy of fine duplex microstructure, the coarse-grained part was penetrated by the fine-grained part due to its high superplasticity, and good joining interface was obtained. When solid joining between fine-grained parts, because both parts had high superplasticity, perfect joining interface with the microstructure of substrate was obtained through grains sliding in thermal plastic deformation, and the joining component had high mechanical properties (σba=533 MPa and δ≈2%). So all the fracture occurred away from the joining interface.