(天津大學(xué) 材料科學(xué)與工程學(xué)院，天津 300350)
摘 要: 重點(diǎn)研究在給定的不同高溫條件下，GH4169電子束焊焊接接頭所表現(xiàn)出的高溫穩(wěn)定性。采用金相、SEM和拉伸等實(shí)驗(yàn)對經(jīng)過不同高溫氧化時間的試樣進(jìn)行顯微組織觀察和力學(xué)性能分析。結(jié)果表明：GH4169電子束焊縫中心區(qū)為樹枝晶和胞狀樹枝晶，由于高溫氧化時間和第二相顆粒釘扎作用的相互影響，晶粒隨著高溫氧化不斷長大，直到25 h時，晶粒尺寸達(dá)到極大值；隨后晶粒大小有減小的趨勢，在50 h以后，晶粒繼續(xù)變得粗大。焊接接頭在650 ℃的高溫氧化下，25 h時機(jī)械拉伸性能達(dá)到最佳，在75 h時接頭的機(jī)械拉伸性能低于常溫接頭的性能；焊接接頭經(jīng)過長時間的高溫氧化，表面會生成較致密的氧化膜。
關(guān)鍵字: 高溫合金GH4169；電子束焊；高溫穩(wěn)定性
（School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China）
Abstract:The stability of GH4169 electron beam welding joints was studied under different high temperature conditions, and its high temperature stability performance under corresponding time conditions was explored. The microstructure and mechanical properties of the samples after different high temperature corrosion time were studied by optical microscope, SEM and tensile test. The results show that the center region of the weld of GH4169 alloy is dendritic and cellular dendritic. Due to the interaction between the high temperature corrosion time and the pinning effect of the second phase particles, the grains grow continuously with high temperature corrosion, reaching a maximum value at 25 h, and then the grain size has a tendency to decrease, and the grains continue to become coarse after 50 h. Under high temperature corrosion at 650 ℃, the mechanical tensile properties of the welded joints reach the best at 25 h, and the mechanical tensile properties of the joints at 75 h are lower than those of the joints without high temperature corrosion. A layer of dense oxide film will be formed on the surface of welded joint after a long time high temperature corrosion.
Key words: GH4169 superalloy; electron beam welding; high temperature stability
