TA2/Q235复合板用Ni基过渡层熔焊接头组织和性能

采用Ni基过渡填充材料，进行TA2/Q235复合板对接熔化焊试验，研究了接头组织形貌、成分分布、相组成及力学性能. 结果表明，近焊缝区，TA2覆层组织主要是板条α相，Q235基层组织为块状珠光体和铁素体；焊缝中Ti层组织主要为呈树枝晶生长的β相，并含有NiTi₂，Ni₃Ti，TiFe，TiFe₂和TiCr₂相，Ni基层中主要是γ-Ni，并含有少量Fe₃Ni₂，CrNi₂和(CrNiMo)化合物，Ti层与Ni基层之间存在宽约50 μm过渡层，过渡层中存在大量针叶状NiTi₂，NiTi金属间化合物，被CrNi₂相包覆，从Ti层到Ni基层，Ti元素缓慢下降，Ni元素先升高后降低，Cr，Mo元素波动升高；Ti层及与Ni基焊缝的过渡层中的金属间化合物和脆性相，提高了硬度，降低了塑韧性.

Microstructure and property of fusion welding butt joints of TA2/Q235 composite plate with Ni alloy transition layers

Fusion welding of TA2/Q235 composite plate was carried out by taking Ni alloy as filled material. The microstructure, chemical, phase composition and mechanical properties of the weld metal were investigated. Results showed that the microstructure of TA2 coating was mainly lath α-phase and microstructure of Q235 matrix was massive pearlite and ferrite near the weld zone. In the weld, microstructure of Ti layer was mainly a dendritic growth of β-phase, containing NiTi₂, Ni₃Ti, TiFe, TiFe₂ and TiCr₂. Microstructure of Ni alloy layer was mainly γ-Ni, and contained a small amount of Fe₃Ni₂, CrNi₂ and (CrNiMo) compounds. Between Ti layer and Ni layer, there was a transition layer width of 50 μm , and a lot of needle were in the transition layer such as NiTi₂ and NiTi intermetallic compound coated by CrNi₂ phase. From the Ti layer to the Ni alloy layer, element Ti decreased slowly, Ni increased first and then decreased and Cr, Mo element increased slowly. The intermetallic and brittle phases in the Ti layer and the transition layer increased the hardness and reduced the ductility.