焊接工艺参数对TA15/304不锈钢真空扩散焊接头组织与抗剪强度影响

Influence of welding process parameters on the microstructure and shear strength of TA15/304SS vacuum diffusion welded joints

针对TA15钛合金与304不锈钢的异种金属连接及其接头进行了研究.结果表明,在850~950℃的焊接温度下,接头扩散区(β-Ti区)和(α+β)-Ti双相区的宽度随温度的升高而增加,元素扩散更充分,接头孔洞逐渐减少,观察到逐渐增加的分层产物.分层产物主要为金属间化合物组成的界面层,即σ-Fe(第1层),FeTi+Fe_(2)Ti(第2层),FeTi+β-Ti(第3层)和β-Ti(第4层).当焊接温度为900℃时,焊接接头达到最大抗剪强度为108 MPa,随着焊接时间的提升,焊接接头的微观形貌,元素成分和物相组织与焊接温度参数接头类似,但焊接时间对接头的抗剪强度影响较小,当焊接时间为80 min时,抗剪强度达到最大,断口出现以韧性为主的脆-韧性混合断裂特征.

A study was conducted on the dissimilar metal connection and joint between TA15 titanium alloy and 304 stainless steel.The experimental results show that at welding temperatures of 850-950℃,the diffusion zone of the joint(β-Ti)District and(α+β)Ti biphasic region increases with the increase of temperature,element diffusion is more complete,joint pores gradually decrease,and an increasing number of layered products are observed.The layered products are mainly interface layers composed of intermetallic compounds,namelyσ-Fe(1st layer),FeTi+Fe_(2)Ti(2nd layer),FeTi+β-Ti(3rd layer)andβ-Ti(4th layer).When the welding temperature is 900℃,the welded joint reaches its maximum shear strength of 108MPa.As the welding time increases,the microstructure and composition of the welded joint are similar to those of the welding temperature parameter joint,but the influence of welding time on the shear strength of the joint is relatively small.When the welding time is 80 minutes,the shear strength reaches its maximum value,and the fracture surface exhibits a brittle ductile mixed fracture feature dominated by toughness.