钛合金线性摩擦焊接头焊接缺陷分析

Analysis of Typical Welding Defects of Titanium Alloy Linear Friction Welding Joint

摘要:

本文选用几种不同工艺参数对TC17钛合金进行线性摩擦焊试验。采用填埋热电偶的方法测量焊接过程中界面温度,运用光学显微镜、扫描电子显微镜等测试手段对接头焊接缺陷进行深入分析,利用显微硬度仪测量了两种不同参数下接头的显微硬度分布。研究表明：当振幅a=1mm时,焊接过程中热输入严重不足,无法得到良好的焊接接头,焊接过程中界面最高温度仅达到相变点附近,而采用a=3mm焊接时,界面温度可以达到1170℃。振幅a=1mm得到的TC17(α+β)/TC17(β)钛合金线性摩擦焊接头界面会出现孔洞、磨损颗粒、氧化物及夹杂、局部未焊合等焊接缺陷。显微硬度测试结果表明：在a=3mm参数下接头焊缝中心显微硬度值最低,相反残留氧化物及夹杂的存在使得振幅a=1mm时得到的接头焊缝中心显微硬度值达到最大。

Abstract:

In this paper, the linear friction welding test was carried out on TC17 titanium alloy by several different welding parameters. The distribution of the interface temperature during the welding process, was measured by embedding the thermol couple, and the OM and SEM technology was applied to analyze the typical welding defects of the joint, the distribution of the joints’ microhardness under two different parameters was measured. The results showed that a sound welded joint cannot be obtained on account of the insufficient heat input in a=1mm. The interface temperature could reach around the phase transition point in a lower amplitude, however, it can reach up to 1170℃ under a=3mm. Additionally, there were welding defects at the interface, such as holes, residual wear particles, oxide layers and inclusions, local unbonded, at a=1mm. The result of the micro-hardness test showed that the microhardness of the joint weld center under a=3mm was the lowest, whereas it reached the maximum value under a=1mm due to the presence of residual oxides and inclusions.