Influence of impurities and deformation temperature on the saturation microstructure and ductility of HPT-deformed nickel
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- 作者：Georg B. Rathmayr ; georg.rathmayr@stud.unileoben.ac.at ; Reinhard Pippan
- 关键词：Severe plastic deformation ; High-pressure torsion ; Nickel ; Carbon ; Influence of impurities
- 刊名：Acta Materialia
- 出版年：2011
- 出版时间：November, 2011
- 年：2011
- 卷：59
- 期：19
- 页码：7228-7240
- 全文大小：2638 K
文摘
Ni with different purities between 99.69 and 99.99 wt. % was deformed by high-pressure torsion (HPT) to high strains, where no further refinement of the microstructure is observed. The HPT deformation temperature varied between ?96 and 400 ¡ãC. Both impurities and temperature significantly affect the lower limit of the grain size obtained by HPT. In the investigated samples, carbon was the most important impurity element in controlling the limit of grain refinement. The decrease in grain size due to an increase in the carbon content from 0.008 to 0.06 wt. % for HPT-deformed Ni samples at room temperature enhanced the ultimate tensile strength from 1000 to 1700 MPa. Surprisingly, the carbon content did not deteriorate the ductility, defined as the reduction in area, which is mainly limited by the total amount of impurities besides carbon. Furthermore, the deformation temperature dependency on ductility was not very pronounced and only visible for deformation temperatures above 200 ¡ãC.