四、弹性变形和压缩空气的作用前面已经谈到,在压制粘土粉末时,会发生塑性变形和弹性变形(图5)。砖坯压制后的弹性后效作用使其在加力方向上发生1～2%的膨胀(随着粘土水分的降低而增大)。在逐渐取消外荷时,砖的高度变化情况如图5曲线2所示。重复施加同样外荷(曲线3),会增加物料的收缩,而且这个附加变形如曲线4所示的残余变形是一定的。因此,二次压制的砖坯比 Fourth, the role of elastic deformation and compressed air As mentioned earlier, when the clay powder is pressed, plastic deformation and elastic deformation occur (Figure 5). The elastic after-effect of the brick after pressing causes it to expand by 1 to 2% in the direction of the force (increasing as the clay moisture decreases). When the external load is gradually removed, the height of the brick changes as shown in curve 2 of Figure 5. Repeated application of the same external load (curve 3) increases the shrinkage of the material, and the residual deformation of the additional deformation as shown by curve 4 is constant. Therefore, the ratio of secondary pressed bricks