【摘要】 为研究TB2钛合金焊接接头性能和显微组织之间的关系,对该合金薄板材料采用了自动钨极氩弧焊焊接.对焊后状态和经过不同热处理的试样进行了室温拉伸、弯曲和硬度试验;进行了光学金相、二次复型、透射以及断口扫描电镜观察;用D—S 型衍射仪进行了相分析.研究表明,TB2 钛合金焊接性能与α相的形态、数量、尺寸关系密切;焊缝金属的时效速度比母材金属快:焊接经二次时效后接头延性显著提高是由于α相端部被钝化了的缘故;晶界附近无析出物区是造成沿晶开裂的主要原因;晶界上析出连续α相对脆性断口有重大影响.更多还原

【Abstract】 The relationship between tensile ductility and microstructure of the weld ofTB2 titanium sheet alloy has been studied.Tensile test,bending test,andhardness test of specimens with and without heat—treatment after automatic TIGwelding have been conducted at ambient temperature.The microstructures andfractured surfaces have been studied by optic microscopy,electron microscopy(replicaand thin foil)and scanning electron microscopy.It has been found that the tensileductility of the weld of TB2 titanium alloy depends on the morphology,quantityand size of the α—phase.The rate of ageing in the weld is higher than that inthe base metal.The tensile ductility of the weld after 2—stage ageing has beenraised considerably due to the blunting of the tips of α—phase precipitates.Thepresence of precipitation—free zone near grain boundaries is responsible for theintercrystalline fracture.The presence of continuous α—phase precipitation alonggrain boundaries embrittles the alloy substantially.更多还原