發(fā)布時(shí)間：2018-11-12 06:36

【摘要】：在微塑性成形過程中,雖然零件的宏觀尺寸達(dá)到了毫米或微米級,但其微觀組織卻沒有發(fā)生明顯的變化,材料的表層晶粒尺寸也就越來越趨近零件的幾何尺寸,導(dǎo)致塑性成形規(guī)律呈現(xiàn)出與宏觀大尺寸零件不同的尺寸效應(yīng)現(xiàn)象。對四種厚度的304不銹鋼薄板試樣進(jìn)行了單向拉伸試驗(yàn)和微彎曲試驗(yàn),測量了薄板的厚度。結(jié)果表明,隨著薄板厚度的減小,塑性變形區(qū)內(nèi)表層晶粒的位錯(cuò)滑移變化對力學(xué)性能和無量綱彎矩的影響越來越顯著,表現(xiàn)出"越薄越強(qiáng)"的尺寸效應(yīng)現(xiàn)象。引入修正的Hall-Petch公式與修正的Nix-Gao應(yīng)變梯度模型,使力學(xué)性能和無量綱彎矩的預(yù)測和試驗(yàn)結(jié)果吻合。
[Abstract]:In the process of micro-plastic forming, although the macroscopic size of the part reaches millimeter or micron, the microstructure of the material does not change obviously, and the grain size of the surface layer of the material becomes more and more close to the geometric size of the part. As a result, the plastic forming law shows different size effect from macroscopically large-sized parts. The specimens of 304 stainless steel sheet with four different thickness were tested by uniaxial tensile test and micro-bending test, and the thickness of the thin plate was measured. The results show that the effect of dislocation slip on mechanical properties and dimensionless bending moment is more and more obvious with the decrease of thin plate thickness. By introducing the modified Hall-Petch formula and the modified Nix-Gao strain gradient model, the prediction of mechanical properties and dimensionless bending moment is in agreement with the experimental results.
【作者單位】： 河北工程大學(xué)機(jī)電工程學(xué)院;
【分類號】：TG142.71

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