Micro parts are more difficult to be formed than macro parts because of size effects. The size effects on the flow stress of copper alloy C3602 with different lubricants were studied. Specimens were heat treated at 350℃ for 1 h and 700℃ for 3 h in nitrogen atmosphere, respectively.The initial diameters of the specimens were varied from 5 to 1 mm with a height-to-diameter ratio h0/D0 = 1.5. Cylinder compression was carried out in the lubrication condition with talc powder, without lubricant, with petroleum jelly, and with vegetable oil. The experiment was carded out at room temperature on a universal testing machine INSTRON 5569 with a strain rate of ε= 0.0025/s. The results show that with the same lubricant, the yield strength decreases with a decrease in specimen size for the specimens annealed at 350℃ for 1 h; however, it in-creases with a decrease in specimen size for the specimens annealed at 700℃ for 3 h. The yield strength decreases with an increase in grain size. The influences of lubricants on yield strength become larger with miniaturization of the specimens.
参考文献
| [1] | M. Geiger;M. Kleiner;R. Eckstein;N. Tiesler;U. Engel .Microforming[J].CIRP Annals,2001(2):445-462. |
| [2] | Geiger M;Merklein M;Tolazzi M.Metal forming ensures innovation and future in Europe[A].Verona,2005:25. |
| [3] | Vollertsen F;Hu Z;Niehoff H S;Theiler C .State of the art in micro forming and investigations into micro deep drawing[J].Journal of Materials Processing Technology,2004,151(1-3):70. |
| [4] | Picart P;Michel J F.Effects of size and texture on the constitutive behaviour for very small components in sheet metal forming[A].Nuremberg,1999:895. |
| [5] | Michel J F;Picart P .Modelling the constitutive behavior of thin metal sheet using strain gradient theory[J].Journal of Materials Processing Technology,2002,125-126:164. |
| [6] | J. F. Michel;P. Picart .Size effects on the constitutive behaviour for brass in sheet metal forming[J].Journal of Materials Processing Technology,2003(3):439-446. |
| [7] | Raulea L V;Govaert L E;Baaijens F P T.Grain and specimen size effects in processing metal sheets[A].Nuremberg,1999:19. |
| [8] | L. V. Raulea;A. M. Goijaerts;L. E. Govaert .Size effects in the processing of thin metal sheets[J].Journal of Materials Processing Technology,2001(1):44-48. |
| [9] | T. A. Kals;Ralf Eckstein .Miniaturization in sheet metal working[J].Journal of Materials Processing Technology,2000(1):95-101. |
| [10] | Jenn-Terng Gau;Chris Principe;Jyhwen Wang .An experimental study on size effects on flow stress and formability of aluminm and brass for microforming[J].Journal of Materials Processing Technology,2007(1/3):42-46. |
| [11] | Engel U;MeBner A;Geiger M.Advanced concept for the FE-simulation of metal forming processes for the production of microparts[A].Ohio,US,1996:903. |
| [12] | Messner A;Engel U;Kals R;Vollertsen F .Size effect in the FE-simulation of micro-forming process[J].Journal of Materials Processing Technology,1994,45(1-4):371. |
| [13] | Chen F K;Tsai J W .A study of size effect in micro-forming with micro-hardness tests[J].Journal of Materials Processing Technology,2006,177(1-3):146. |
| [14] | Ulf Engel .Tribology in microforming[J].Wear: an International Journal on the Science and Technology of Friction, Lubrication and Wear,2006(3):265-273. |
| [15] | Zeng J F .Fundamental Research on Size-Effect in Microforming[D].Taiwan University,Taibei,2004. |
| [16] | 陈志英,许树勤,董湘怀,阮雪榆.6063铝合金压缩实验摩擦修正及高温流动应力模型[J].材料科学与工艺,2008(06):847-851. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%