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对经过超细化处理的45钢试样,在不同变形温度及不同应变速率下进行了超塑性拉伸试验,并与退火状态试样作了对比,试验结果表明,在一定条件下45钢可以呈现良好的超塑状态。其应变速率敏感性指数m达0.6以上,最小流动应力为4.4MPa,最大拉伸延伸率达584%。试验中发现,当经超细化处理的45钢在Ac_1点进行恒温拉伸试验时,其超塑性延伸率指标出现一个陡峭的峰值。这一现象的发现对恒温超塑性机理的研究,以及建立比较合理的超塑性变形的模型,都将产生一定的影响. 本文的研究成果已在精密型腔模超塑成形技术中得到应用,显示了优质,高效的综合优势,具有广阔的应用前景.
The superplastic tensile test was carried out on the 45 steel samples after the ultrafine treatment at different deformation temperatures and different strain rates, and compared with the annealed samples. The experimental results show that under certain conditions, 45 steel can Show a good super-plastic state. The strain rate sensitivity index m is above 0.6, the minimum flow stress is 4.4MPa and the maximum tensile elongation reaches 584%. It was found in the experiment that the superplastic elongation index of 45 steel produced by ultrafine treatment showed a steep peak at Ac_1 when it was subjected to constant temperature tensile test. The discovery of this phenomenon will have certain influence on the research of thermostatic superplasticity mechanism and the establishment of a more reasonable model of superplastic deformation.The research results of this paper have been applied in the precision cavity mode superplastic forming technology, The high quality, high efficiency and comprehensive advantages, has a broad application prospects.