GH4169镍基高温合金轴向摩擦焊接头微观组织与力学性能

发布时间：2018-03-22 09:21

  本文选题：GH4169合金摩擦焊　切入点：微观组织　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：GH4169镍基高温合金由于其在高温下具有高强度、塑性、良好的抗氧化性、抗耐热腐蚀性、断裂韧性和疲劳性能等优点,而被广泛应用于航空发动机压气机盘、涡轮盘、机匣、压气机叶片和紧固件等热端部件上,而优质高效的焊接工艺是保证高温合金材料在航空发动机热端部件能够满足精度、性能以及可靠性要求的关键技术。作为一种优质高效、环境友好的固相焊接技术,摩擦焊具有工艺控制参数少、热输入低、变形小、尺寸精度高等独特优势,尤其适用于高温材料的焊接,并已经成功应用于国外多种先进商用航空发动机热端部件的制造。基于此,本文研究了 GH4169镍基高温合金轴向摩擦焊接工艺,在试验范围内获得最优焊接工艺参数:摩擦压力P1=100MPa、摩擦时间t1=10 s、转速n=2200 rpm、顶锻压力P2=200MPa以及顶锻时间t2=10s。对最优接头进行常温与高温(650℃)拉伸性能测试,试验结果表明,试样在常温拉伸与高温拉伸条件下均断裂在母材,常温拉伸时平均强度为800MPα,延伸率为60%,断面收缩率为69.75%。高温拉伸强度为649.6 MPa,延伸率为60%,断面收缩率为41.2%。对接头微观组织分析得出,随着摩擦压力的增大,焊接接头的变形区从椭圆状变为"B"型形貌,最终呈现"哑铃"状形貌。而随着摩擦时间的增加,试样的微观形貌并没很大的改变。焊接后接头处存在超细晶区、细晶区以及热力影响区,在这些区域内都存在母材原有的(Nb,Ti)(C,N)化合物,超细晶区部分(Nb,Ti)(C,N)化合物发生了破碎、氧化。在焊接过程中,随着摩擦压力和摩擦时间的增加,热输入增加,变形区宽度增加,试样中心变形区最后演变为细晶区和热力影响区,试样边缘变形区最后演变为超细晶区、细晶区和热力影响区。随着摩擦压力的增加,非界面处的区域宽度增加,晶粒度减小。随着摩擦时间的增加,试样中心各区域宽度增加,晶粒度也增加。而试样边缘超细晶区宽度减小,细晶区宽度先增大后减小,晶粒度减小,热力影响区宽度增加,晶粒度减小。当热输入很大时,焊缝中心处热力影响区晶界上形成y/Laves共晶相,分析认为GH4169合金摩擦焊接过程中在热输入较大的条件下在热力影响区发生了成分液化,通过离异共晶的方式生成y/Laves共晶相。
[Abstract]:Because of its high strength, plasticity, good oxidation resistance, heat resistance, fracture toughness and fatigue properties, GH4169 nickel-base superalloy is widely used in aero-engine compressor disc, turbine disk, casing, etc. In hot end parts such as compressor blades and fasteners, high quality and high efficiency welding technology is the key technology to ensure that superalloy materials can meet the requirements of accuracy, performance and reliability in the hot end parts of aeroengine. Environment friendly solid phase welding technology, friction welding has a few process control parameters, low heat input, small deformation, high dimensional accuracy and other unique advantages, especially suitable for high temperature materials welding, And has been successfully used in the manufacture of hot end parts of many advanced commercial aero engines abroad. Based on this, the axial friction welding process of GH4169 nickel base superalloy is studied in this paper. The optimum welding process parameters are obtained in the range of test: friction pressure P1n 100MPa, friction time T110s, rotational speed N2200rpm, top forging force P2=200MPa and top-forging time t210s.The tensile properties of the optimal joint are tested at room and high temperature (650 鈩，

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