Study on phase and texture of TC17(α + β)/TC17(β) linear friction welding joint

The linear friction welded joints of TC17(α + β)/TC17(β) titanium alloy were tested and analyzed by electron backscatter diffraction technique. Phase identification and texture analysis were carried out on each part of the joint. The results show that compared with the parent metal, the α phase of thermo-mechanically affected zone decreases, and the β phase of the joint increases as weld. Due to the rapid cooling of the weld zone, dynamic recrystallization occurs at the weld joint, and a large number of metastable β phase grains are formed. The texture distribution density of TC17(β) side base metal and thermo-mechanically affected zone is stronger than TC17(α + β) side. The joint displayed texture (5 4 6)1 \bar 3 \bar 3 in the as-welded weld zone. The rolling plane is approximately parallel to (1 1 1). After heat treatment at 610 °C, the metastable β phase of the weld zone decomposes to form a fine secondary α phase and β phase. Compared with the as-welded weld, the crystal of the weld zone is slightly rotated after postweld heat treatment, and the texture strength development, exhibited (5 5 7)\overline 11\; \overline 17 20 texture. The crystal orientation of the weld zone has a preferred orientation in which the normal direction is close to 1 1 1 and the rolling plane is close to (1 1 1).