金刚石印压微孔成形机理与试验分析
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摘要
金刚石印压成孔是一种新型微孔印压成形方法,在工业中具有重要的应用价值。为了提高金刚石纳米印压微孔的质量,必须先从其成形机理入手开展研究。从宏观力学角度分析了微孔成形的具体过程,采用分子动力学分析方法从微观晶体力学角度分析了印压成孔过程中材料变形和微孔成形规律,预测了孔边沿裂纹的产生,并结合理论分析和印压加工试验进行了验证。结果表明:微裂纹是应力高度集中下位错运动受阻于晶界和其它晶内结构而产生;通过调节压头卸载速率和铜片晶粒尺寸,可有效抑制微裂纹的萌生和扩展,提高成孔质量。
Diamond coining is a new type of micropore forming method,which has important application value in industry. In order to improve the forming quality of micropores,it is necessary to start with the formation mechanism. The specific process of micropore forming is analyzed from the perspective of macro-mechanics,and molecular dynamics analysis method is used to analyze the deformation and micropore forming rules in the process of indentation forming micropores from the perspective of microscopic crystal mechanics,and the occurrence of edge cracks at the edges is also predicted. Combined with theoretical analysis and printing pressure processing experiments,theories drawn above are verified. The results show that the dislocation movement is hindered by grain boundaries and other intragranular structures leading to crack initiation under stress concentration. By adjusting the pressure head unloading rate and copper grain size,the initiation and propagation of micro-cracks can be effectively inhibited,thus improving the quality of micropore formation.
Diamond coining is a new type of micropore forming method,which has important application value in industry. In order to improve the forming quality of micropores,it is necessary to start with the formation mechanism. The specific process of micropore forming is analyzed from the perspective of macro-mechanics,and molecular dynamics analysis method is used to analyze the deformation and micropore forming rules in the process of indentation forming micropores from the perspective of microscopic crystal mechanics,and the occurrence of edge cracks at the edges is also predicted. Combined with theoretical analysis and printing pressure processing experiments,theories drawn above are verified. The results show that the dislocation movement is hindered by grain boundaries and other intragranular structures leading to crack initiation under stress concentration. By adjusting the pressure head unloading rate and copper grain size,the initiation and propagation of micro-cracks can be effectively inhibited,thus improving the quality of micropore formation.
引文
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[3]Lawn B R,Evans A G.A model for crack initiation in elastic/plastic indentation fields[J].Journal of Materials Science,1977,12(11):2195-2199.
[4]杨顺华.晶体位错理论基础[M].北京:科学出版社,1988.
[5]曹伟,肖杰.微纳尺度断裂的分子动力学模拟[J].国外电子测量技术,2015,34(3):23-26.
[6]陈丽群,王崇愚,于涛.bcc Fe中刃型位错的结构及能量学研究[J].物理学报,2006(11):5980-5986.
[7]汪复兴.金属物理[M].北京:机械工业出版社,1980.