【作者】 田世英；

【导师】 许鸿吉；

【作者基本信息】 大连交通大学 ， 材料加工工程， 2006， 硕士

【摘要】 作为镍基变形高温合金的一种，GH4169合金在-253～700℃范围内具有良好的综合性能，能够制造各种复杂的零部件，在宇航、核能、石油工业中获得了极为广泛的应用。 本课题采用钨极氩弧焊，对厚度为1.5mm的GH4169合金板材进行连接，并对部分接头进行滚压处理。按照相关的航空试验标准，通过温拉伸、弯曲、硬度、650℃高温拉伸和持久试验，并采用光镜、扫描电镜、能谱等分析手段，对母材和接头的力学性能、断口形貌、组织形态进行了研究。 试验结果表明：GH4169合金室温及高温拉伸时均为韧窝断口，持久拉伸断口以韧窝为主，也有准解理断口。氩弧焊接头室温拉伸时断裂部位在母材，为韧窝断口，高温拉伸和持久拉伸时断在焊缝或熔合区，高温拉伸时断口为贝壳状，而持久拉伸时为准解理甚至沿晶的脆性断口。接头的高温拉伸强度和持久强度略低于母材，室温和高温塑性要低于母材。母材和氩弧焊接头均有良好的弯曲性能。热影响区的显微硬度高于焊缝。焊后对接头进行滚压处理可提高焊态接头的力学性能。室温下母材组织呈条带状，奥氏体晶粒比较细小。氩弧焊接头焊缝金属的室温组织为铸态树枝晶，近缝区奥氏体晶粒由于过热而长大，偏析组织以白色针片状出现于树枝晶间，γ″、γ′强化相在偏析组织中的数量要多于其在奥氏体树枝晶内的量；经长时间高温处理后母材奥氏体形状规则，晶粒比室温时粗大。长时间高温处理后氩弧焊接头焊缝的组织形态和室温组织基本一样，二者的区别在于：经长时间高温处理后焊缝树枝晶间的偏析组织变少，而碳化物的数量增多。更多还原

【Abstract】 As one kind of Ni-based wrought superalloy, GH4169 can is manufactured into many complex parts and is wildly used in following fields, such as astronavigation, atomic energy, oil and so on, at the temperature range of -253-700℃. This thesis reports an investigation on the microstructure and physical properties of base metal and Argon-arc welding joint of Ni-based GH4169 superalloy.GH4169 superalloy plates of 1.5mm-thickness were jointed by Argon-arc welding and part of joints was rolling-treated. Tensile tests at room temperature and 650℃, blend, stress-rupture and microhardness tests were finished according to involved astronavigation standards. Physical property, fracture appearance and microstructure of the joints were studied by means of optical, scanning electron microscopes, energy spectrometer.The fracture of the alloy is featured with dimple in tensile test both at room and high temperature, mixed mechanism fracture, existing both dimples and tear ridges, is labeled with the alloy in creep rupture. The position where the joints got cracking almost at fusion area or welded seam at 650℃ while cracked at base metal at room temperature. Tensile fracture of joint is dimple at room temperature while conchoidal fracture belongs to high tensile and inter-granular and quasicleavage are with stress-rupture tensile. Stress-rupture strength of the joints is equivalence to the value the base metal has, while plasticity gets deteriorating both at room and high temperature. Microhardness value in HAZ is higher than that in welded zone. Physical properties of the rolled joint are better than unrolled joints’. Austenite microstructure of the alloy is featured with banding at room temperature while regular pattern through long-time high temperature, and更多还原