(北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083)
摘 要: 采用定向凝固法，在氫氣壓力為0.2 MPa，熔體溫度為1 200 ℃的條件下制備d 45 mm×120 mm的藕狀多孔純銅棒材，研究藕狀多孔金屬垂直于氣孔方向的壓縮變形過程及其影響因素，分析壓縮變形機理。結(jié)果表明：藕狀多孔銅沿垂直于氣孔方向的壓縮變形過程可分為彈性變形、氣孔的塑性屈曲、氣孔的密實化和密實化后的塑性變形4個階段，其中塑性屈曲階段的主要變形機理為多孔材料在垂直載荷的作用下先后形成若干個變形帶，在變形帶內(nèi)圓形氣孔先后以壓扁和塌陷的方式進(jìn)行塑性變形；采用回歸分析方法建立藕狀多孔金屬沿垂直于氣孔方向的壓縮變形本構(gòu)關(guān)系。
關(guān)鍵字: 氣體/金屬共晶定向凝固；藕狀多孔金屬；壓縮變形；變形行為；本構(gòu)關(guān)系
（School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The lotus-type porous copper bars with 45 mm in diameter and 120 mm in length were fabricated by unidirectional solidification at hydrogen pressure of 0.2 MPa and molten temperature of 1 200 ℃. The compressive deformation process of the lotus-type porous copper with pore perpendicular to the compressive direction and its effect factors were investigated. The deformation mechanism of lotus-type porous copper with pores perpendicular to the compressive direction was also analyzed and discussed. The results show that the deformation of the lotus-typed porous copper consists of four stages of elastic deformation, plastic yield deformation, densification and plastic deformation after densification. The main deformation mechanism in the plastic yield stage is that several deformation bands generate sequentially under the perpendicular loading, and in these deformation bands the pores are deformed by flattening and collapsing sequentially. Based on the above results, the compressive mechanical model of the lotus-type porous metals with pores perpendicular to the compressive direction is established using the method of linear regression.
Key words: gas-metal eutectic unidirectional solidification; lotus-type porous metal; compressive deformation; deformation behaviors; constitutive relation
