| 引用本文: | 许宁,王峰会,罗金恒.X80管线钢焊接接头微观断裂行为的TEM原位观察[J].材料科学与工艺,2015,23(5):71-76.DOI:10.11951/j.issn.1005-0299.20150513. |
| XU Ning,WANG Fenghui,LUO Jinheng.In-situ TEM observation of micro-fracture behavior of X80 pipeline steel welding joint[J].Materials Science and Technology,2015,23(5):71-76.DOI:10.11951/j.issn.1005-0299.20150513. |
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| 摘要: |
| 为了从微纳米尺度研究管线钢的断裂方式,通过透射电镜原位拉伸方法,从焊缝区和热影响区直接取样,直观测试了X80管线钢在晶粒尺度范围的裂纹生长、扩展等断裂过程和机理.研究表明:在原位拉伸过程中,晶内发射的螺型位错与刃型位错速率之比约为41；晶界裂纹为不连续扩展,而裂纹在晶内沿其DFZ的方向萌生扩展,其扩展是连续的.在加载过程中,裂纹会越过晶界扩展,当裂纹越过大角度晶界时,裂纹扩展方向改变约为30°,扩展方式也会有所变化；当裂纹越过小角度晶界时,裂纹扩展方向不变,扩展方式也不变. |
| 关键词: X80管线钢 TEM原位拉伸 断裂行为 晶界 位错运动 |
| DOI：10.11951/j.issn.1005-0299.20150513 |
| 分类号:TG111.91 |
| 基金项目:西北工业大学研究生创意创新种子基金资助项目(Z2015087). |
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| In-situ TEM observation of micro-fracture behavior of X80 pipeline steel welding joint |
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XU Ning1, WANG Fenghui1, LUO Jinheng2,3
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(1.School of Mechanics, Civil Engineering and Architecture,Northwestern Polytechnical University, Xi′an 710129,China; 2.School of Materials Science and Engineering, Xi′an Jiaotong University,Xi′an 710049,China; 3.Tubular Goods Research Centre, CNPC,Xi′an 710065,China)
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| Abstract: |
| In the welded transportation pipeline, the fusion zone and heat affected zone have more scientific significance regarding the fracture and failure studies. In this paper, samples from the fusion and heat affected zones were examined, and the crack growth and propagation of the X80 pipeline steel were tested through in-situ tensile in transmission electron microscope (TEM). The results showed that, during the tensile process, the crack was initiated and propagating along the direction of DFZin the crystal. The ratio of screw dislocation to edge dislocation emission rate in the crystal was 41. The crack expansion along the grain boundary was not continuous, while the intra-granular crack expansion was continuous. Cracks were able to cross the grain boundaries during the loading step. When the crack passed through high angle grain boundaries, the direction of the crack propagation changed about 30°, and the mode of crack propagation was also changed. When the crack went across the low angle grain boundary, the direction and mode of crack propagation remained unchanged. |
| Key words: X80 pipeline steel TEM in-situ tension fracture behavior grain boundary movement of dislocations |
