毕业设计（论文）-钛合金超塑性连接技术及应用.doc

钛合金超塑性连接技术及应用
摘要
本文通过试验验证了钛合金具有良好的超塑性,及其影响断后延伸率的两个主要因素为:初始应变速率、变形温度。其中初始应变速率对钛合金超塑性变形有着更显著的作用。文中试验采用用相变超塑性扩散焊法实现了钛合金和奥氏体不锈钢的连接,在循环上限温度850~970℃、循环下限温度760~840℃、循环次数2~45、焊接压力3~10 MPa、循环加热速度l5~60℃/s的范围内观察了工艺参数对接头强度的影响。得到试验条件钛合金与不锈钢焊接的优化工艺参数为: Tmax=890℃、Tmin=800℃、N=l0、P=5 MPa、Vh=30℃/s。在此工艺条件下,接头强度达到307 MPa,而焊接时间仅为160s。钛合金与不锈钢扩散焊接接头从不锈钢侧开始依次形成了α、Fe2Ti、FeTi和β-Ti层,在不锈钢侧还形成了少量的NiTi。拉伸试验时,接头沿FeTi和β-Ti层之间的某一个位置断裂,β-Ti承受了主要的拉力,而FeTi金属间化合物层是接头的薄弱环节。
关键词:钛合金,超塑性,相变超塑性,扩散连接
SUPERPLASTIC TITANIUM
CONNECTING TECHNOLOGY
AND ITS APPLICATION
ABSTRACT
In this paper, the test has good superplastic titanium alloy, make elongation and impact of the two main factors: the initial strain rate, deformation temperature. Which the initial strain rate superplastic deformation of titanium alloy has a more prominent role. In this paper, the use of phase change with superplastic diffusion bonding method of the titanium alloy and austenitic stainless steel connection, the upper limit temperature in the cycle of 850 ~ 970 ℃, the minimum temperature cycle of 760 ~ 840 ℃, cycles 2 ~ 45, welding pressure of 3 ~ 10 MPa, heating rate cycle l5 ~ 60 ℃/ s within the scope of the inspection process parameters on joint strength. Were put to the test conditions of titanium and stainless steel welding for the optimization of process parameters: Tmax = 890 ℃, Tmin = 800 ℃, N = l0, P = 5 MPa, Vh = 30 ℃/ s. In the process conditions, the joint strength reached 307 MPa, and the welding time is only 160s. The proliferation of titanium alloy and stainless steel stainless steel side of welded joints from the start followed by the formation of the α, Fe2Ti, FeTi and β-Ti layer, also formed in the stainless steel side of a small amount of NiTi. Tensile test, the joints along the FeTi and β-Ti layer to a position between the fracture, β-Ti to bear the main rally, and FeTi pound layer is the weak link connector.
KEY WORDS: Titanium Alloys, Superplasticity, Phase Transformation Superplasticity, Diffusion Bonding
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