采用电弧焊对20 mm厚的2519-T87高强铝合金进行表面堆焊，观察了 部分熔化区出现的无析出物区(PFZ)的组织特征，并对该区域的 形成机理进行了研究. 结果表明：无析出物区的形成主要 是晶界液化层迁移所导致的，迁移的驱动力为相干应变能， 焊缝收缩引起前、后晶粒的应变能差以及晶界曲率引起的界面能差. 焊接热输入对无析出物区的形成有一定影响，随着焊接热输入的增加， 无析出物区的宽度亦增加. 该区的存在使部分熔化区在拉伸和冲击过程中 易于断裂，且断裂方式为沿晶断裂.
The microstructure in the partially melted zone of an arc-welded 20mm thickness 2519-T87 high strength aluminum alloy is investigated, an oriented precipitate-free zone is found behind the grain boundary, and this zone is not uniformly surrounding the grain, but usually oriented toward the fusion line. The formation mechanism of this zone is also studied. Results indicate that the mechanism of grain boundary liquid film migration is favored the formation of the precipitate free zone, the driving forces include coherency strain energy, the differential strain energy between the two grains induced by the elastic stresses generated during welding and differential surface energy due to grain boundary curvature. And with the increase of heat input, the thickness of the precipitate free zone increase. The precipitate free zone is harmful to the mechanical property of partially melted zone, and the fractography of PMZ showing the intergranular fracture.
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| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] |
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