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热浸铝镀层的微观结构及形成机理 总被引:15,自引:6,他引:15
在一定温度下,研究了Q235钢在不同时间条件下热浸铝时镀层的微观结构变化及形成机理。结果表明,浸铝初期,在铝铁界面产生连续的FeAl3薄层;随时间延长,由于斜方晶格Fe2Al5相的快速生长,抑制了FeAl3相的进一步形成,使FeAl3相由初期的连续层向非连续相层转变,而Fe2Al5相呈不均匀齿状垂直于基体表面生长。通过SEM及TEM分析了镀层形成机理并提出了镀层的结构模型。 相似文献
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稀土对电沉积Ni-P合金镀层显微组织的影响 总被引:9,自引:0,他引:9
研究了在镀液中添加稀土元素后Ni P合金镀层显微组织的变化。X射线衍射及透射电镜分析结果表明 ,在镀液中添加一定量的稀土元素 ,明显地促进了Ni P合金微晶组织向非晶态组织转变 ,从而提高Ni P合金镀层的耐蚀性。电化学极化曲线测试结果表明 ,稀土元素能够促进电沉积过程的阴极极化。由于稀土离子的特性吸附抑制了合金原子在电极界面的正常形核 ,因而促进了非晶组织的形成。 相似文献
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16Mn钢奥氏体化后冷却时,随等温温度降低及冷却速度加快,显微组织由块状铁素体变成魏氏组织;而魏氏组织中的针状铁素体由交叉分布变成平行分布。我们过去的工作表明,当形成以交叉针状铁素体为主的魏氏组织时,钢材的抗冷脆性最好。本文研究了16Mn钢中交叉针状魏氏组织的形成条件,提出了采用“双段控冷工艺”,可在较宽的工艺条件下得到交叉针状魏氏组织。 相似文献
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Measurement of Residual Stress Field of Hardfacing Metal with RE Oxide and Its Numerical Simulation 总被引:1,自引:0,他引:1
The temperature and residual stress fields of a medium-high carbon steel, welded by a cracking resistance electrode with rare earth (RE) oxide, were measured by thermo-vision analyzer and X-ray stress analyzer respectively. Meanwhile, the martensitic transformation temperatures of matrix, hard-face welding (hardfacing) metal welded by conventional hardfacing electrode and that welded by cracking resistance electrode with RE oxide were determined. According to the experimental data and the thermo-physical, mechanical parameters of materials, finite element method (FEM) of temperature and stress fields was established. In this FEM, the effect of martensitic transformation on residual stress of hardfacing metal of medium-high carbon steel was taken into account. The results show that, by adding RE oxide in the coat of hardfacing electrode, the martensitic transformation temperature can be decreased, so that the residual tensile stress on the dangerous position can be decreased. Therefore, the cracking resistance of hardfacing metal can be improved. 相似文献
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退火态TC4合金的热变形行为 总被引:1,自引:0,他引:1
采用Gleeble-3 5 0 0热模拟机系统研究退火态TC4(Ti 6Al 4V)合金在75 0~95 0℃,应变速率0 0 0 1~1s- 1 条件下的热变形行为。TC4合金的热变形激活能约为482kJ/mol,热变形方程为ε′=2 95×10 1 9[sinh(α·σp) ] 2 4 9exp(-4 82 0 0 0 /RT)。不同真应变下的热加工图相似,随变形温度升高及应变速率降低,能量消耗效率η逐渐升高。在变形温度90 0℃左右、应变速率为0 0 0 1s- 1 时,能量消耗效率η达到峰值,约为5 8%。 相似文献