The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo2B2 formation was also studied. Finally, the effects of boron contents ...The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo2B2 formation was also studied. Finally, the effects of boron contents and FeMo2B2 formation on the high temperature strength were studied. Boron atoms were segregated to prior austenite grain boundary during normalizing treatment. And these boron atoms were slowly diffused into the grain interior during tempering and aging at 700 ℃. The FeMo2B2 phase was only formed after 1,000 h aging at 700 ℃ in alloy containing 196 ppm boron. The formation of FeMo2B2 phase is accelerated by the applied stress. It was expected that the formation of FeMo2B2 is closely related to the redistribution of boron atoms. The tensile strengths at 700 ℃ are increased with the increase of boron contents. However, the formation of FeMo2B2 phase results in lower tensile strength.展开更多
A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation...A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.展开更多
目的观察抗旋转股骨近端髓内钉(Proximal femoral nail antirotation,PNFA)微创手术治疗老年不稳定股骨粗隆间骨折的临床疗效。方法自2010年5月至2011年6月回顾性研究老年性不稳定股骨粗隆间骨折35例,男9例,女26例,年龄65～92岁,平均74....目的观察抗旋转股骨近端髓内钉(Proximal femoral nail antirotation,PNFA)微创手术治疗老年不稳定股骨粗隆间骨折的临床疗效。方法自2010年5月至2011年6月回顾性研究老年性不稳定股骨粗隆间骨折35例,男9例,女26例,年龄65～92岁,平均74.3岁。按改良Jensen-Evans分型:ⅢA型14例,ⅢB型9例,Ⅳ型2例。均合并不同程度的骨质疏松。在C型臂透视下闭合复位经皮小切口PFNA内固定治疗。结果手术时间45～85min,平均63.9min;术中出血50～150ml,平均80ml,手术切口3～6cm,平均5cm。随访时间6～12个月,平均8.7个月。骨折全部愈合,愈合时间9-18周,平均12.5周。按Harris髋关节功能评分标准:优25例,良8例,可2例,优良率为94.3%。结论经皮微创PFNA治疗老年性不稳定股骨粗隆间骨折疗效良好,具有骨折固定牢固,创伤小,术后并发症少等优点。展开更多
基金This work was financially supported by the Ministry of Commerce,Industry and Energy of Korea.
文摘The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo2B2 formation was also studied. Finally, the effects of boron contents and FeMo2B2 formation on the high temperature strength were studied. Boron atoms were segregated to prior austenite grain boundary during normalizing treatment. And these boron atoms were slowly diffused into the grain interior during tempering and aging at 700 ℃. The FeMo2B2 phase was only formed after 1,000 h aging at 700 ℃ in alloy containing 196 ppm boron. The formation of FeMo2B2 phase is accelerated by the applied stress. It was expected that the formation of FeMo2B2 is closely related to the redistribution of boron atoms. The tensile strengths at 700 ℃ are increased with the increase of boron contents. However, the formation of FeMo2B2 phase results in lower tensile strength.
文摘A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.
文摘目的观察抗旋转股骨近端髓内钉(Proximal femoral nail antirotation,PNFA)微创手术治疗老年不稳定股骨粗隆间骨折的临床疗效。方法自2010年5月至2011年6月回顾性研究老年性不稳定股骨粗隆间骨折35例,男9例,女26例,年龄65～92岁,平均74.3岁。按改良Jensen-Evans分型:ⅢA型14例,ⅢB型9例,Ⅳ型2例。均合并不同程度的骨质疏松。在C型臂透视下闭合复位经皮小切口PFNA内固定治疗。结果手术时间45～85min,平均63.9min;术中出血50～150ml,平均80ml,手术切口3～6cm,平均5cm。随访时间6～12个月,平均8.7个月。骨折全部愈合,愈合时间9-18周,平均12.5周。按Harris髋关节功能评分标准:优25例,良8例,可2例,优良率为94.3%。结论经皮微创PFNA治疗老年性不稳定股骨粗隆间骨折疗效良好,具有骨折固定牢固,创伤小,术后并发症少等优点。
