Mechanism of intermediate temperature embrittlement in Ni( Bi) alloy
- 作者：ZHENG LeiMENG YeYANG WuqiangXU Min
- 会议时间：2013-06-01
- 关键词：nickel alloy ; grain boundary segregation ; atom probe tomography ; tensile test ; embrittlement
- 作者单位：School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China
- 母体文献：第五届宝钢学术年会论文集
- 会议名称：第五届宝钢学术年会
- 会议地点：上海
- 主办单位：中国金属学会
- 语种：chi
摘要
Tensile ductility of Ni( Bi) alloy and high purity Ni are tested at room temperature and elevated temperatures in the range of 400℃ to 850℃ after various thermal pre-treatments.Room-temperature tensile ductility of Ni( Bi) alloy reveals clear minimum after a critical time of isothermal pre-annealing at 750℃ or 650℃.Elevated-temperature tensile ductility of the alloy shows evident intermediate temperature embrittlement with minimum ductility between 700℃ and 750℃,while that of high purity Ni does not.Fractography demonstrates intergranular fracture for samples of low ductility.Furthermore,atom probe analysis indicates a strong tendency of Bi segregation to grain boundaries in nanocrystalline Ni-3at% Bi layer.Based on these observations,non-equilibrium grain-boundary segregation of Bi is identified to control intermediate temperature embrittlement in Ni(Bi) alloy.