The use of commodity polymers in many technical applications is limited due to its material behavior - thermal stability, barrier properties, toughness or mechanical strength. That is the reason why to modify the basic polymer with fillers, reinforcement at different macroscale, microscale as well as nanoscale level. All the physical and chemical properties can be modified by way of fillers. The goal is find the way how to enhance the toughness of this system by keeping its stiffness.[l,2,3,] The first step is to modify relevant parameters of the matrix at molecular as well as super molecular level (adding a and p nucleation agent). Effect of particles on the properties and behavior of system strongly depends on its size, shape, surface coating and distribution. Mechanisms of toughening (creation of shear bands) can starts after releasing the stress concentration on the interface. [4,5,6] The system PP matrix filled with rigid submicroscopic particles of CaCC>3 was confrontate with system PP/kaolin, PP/ talc. Tensile test was applied to estimate the tensile properties. The fracture mechanics approach was chosen to describe the toughness of the system. Particularly, the J-R curve procedure was used. The results were reviewed with microscopy observation.
The cast aluminium alloy A357 has been widely used in aircraft industry. Particularly, due to well known performance characteristics of aluminium alloys like strength/weight ratio (specific strength). This contribution deals with the effect of different heat treatment on mechanical characteristics of A357 cast aluminium alloy. As relevant parameters were chosen yield strength, ultimate strength, elongation and hardness. The material parameters were obtained using standard tensile test method and hardness measuring. Finally the obtained values of mechanical characteristics were compared with results which were publicized in literature.
This work deals with problems of measuring the fracture toughness of alumina alloys. The possibilities of measuring the fracture toughness at small specimen were experimentally investigated. Cast alumina alloy AlSi9Cu3 and wrought alumina alloy EN-AW 6082/T6 were taken as experimental objects.