CAJ | 학술논문

为研究304不锈钢超薄板力学性能与试样尺寸、晶粒尺寸的相关性，应用自制的超薄板专用夹具进行拉伸试验，分析超薄板的厚度、晶粒尺寸对材料力学性能的影响。试验结果表明，随着试样厚度减小，材料的屈服强度先减小而后明显增大。这是因为，当试样厚度大于200μm时，表面层效应起主导作用；当试样厚度小于200μm时，应变梯度效应和表面层钝化膜共同作用。同一厚度下，改变试样的晶粒尺寸结果表明，当厚度尺寸和晶粒尺寸的比值小于2时，板料在厚度方向已没有内部晶粒，位错很容易滑移出自由表面，应力‐应变曲线显著降低。
위연구304불수강초박판역학성능여시양척촌、정립척촌적상관성，응용자제적초박판전용협구진행랍신시험，분석초박판적후도、정립척촌대재료역학성능적영향。시험결과표명，수착시양후도감소，재료적굴복강도선감소이후명현증대。저시인위，당시양후도대우200μm시，표면층효응기주도작용；당시양후도소우200μm시，응변제도효응화표면층둔화막공동작용。동일후도하，개변시양적정립척촌결과표명，당후도척촌화정립척촌적비치소우2시，판료재후도방향이몰유내부정립，위착흔용역활이출자유표면，응력‐응변곡선현저강저。
In order to investigate the specimen size dependence and grain size dependence on the mechanical properties for SS304 ultrathin sheet metal ,the uniaxial tensile tests were performed by using self‐designed special fixture for ultrathin sheet metal .The influence of ultrathin sheet metal thickness and grain size on the material properties were analyzed .The experiment results showed that with the decreasing of sheet metal thickness ,the material yield strength decreased at first and then increased significantly . Because when the sheet metal thickness was larger than 200μm ,surface layer effect played a dominant role;to the contrary ,be‐cause of the dual action of strain gradient effect and surface passivation membrane ,the yield strength is decreased .What's more , the grain size has been changed under the same thickness ,so when sheet metal thickness‐grain size ratio was less than 2 ,the dis‐location was easy to slip out of the free surface and the stress strain curve decreased significantly .