Rotational deformation mode of porous structures

We consider the process of deformation and buckling of flow during compression of the porous structure on the basis of aluminum with a high concentration of pores. The starting material is AMg6 alloy powder having a particle size of less than 1 mm. Compression tests are performed at an average rate of 1 mm / min. Loading at a temperature T = 293 K was carried out to a certain strain, then the test sample was photographed and stayed. The authors analyzed rotary modes of plastic flow and theirrelationship with the beginning of the fracture process. In order to do this, we allocated reference points - the joints and then determined their trajectory in the process of loading. We established the important role of nonuniform rotation associated with strong heterogeneity of the porous structure. Nonuniform rotation in the vicinity of large central pores lead to a collapse of the two neighboring pores and subsequent destruction. Phenomenology process was as follows: inhomogeneous rotation in the vicinity of large central pores lead to a collapse of two large and one medium-sized pores. This rotation "pulled" the displacement of two small pores related to them, etc. The concentration of large pores (3-5 times larger than the average size) was small 10-2; their statistics lied on the so-called "tail of the distribution" areas where statistical methods were ineffective, i.e. limit inequalities and theorems of probability theory were not executed. These areas ultimately determined moment buckling and fracture of the porous structure. Having a small number of large pores reduced the ultimate strain of 10-15 % and power consumption of the structures 25-35 %.