Effect of Different Modifiers and Heat Treatment on Structure, Hardness and Microhardness of AlSi7Mg0.3 Alloy

The aim of the submitted paper is to study the influence of the speed of the penetration of the indenter into the test piece ranging from 0.302 μm s -1 to 1.089 μm s -1 and applied load ranging from 10 g to 100 g on measured values of micro-hardness. Whereas certified reference material with defined specified hardness and its uncertainty was used as a test piece, the measurement involved indirect calibration of the tester. The influence of observed factors on measured value of the micro-hardness was evaluated by Meyer's index n, PSR method and by Analysis of Variance (ANOVA). The influence of the load on the measured value of micro-hardness is statistically significant and the relationship between applied load and micro-hardness manifests "reverse" ISE. The velocity has statistically significant effect on the micro-hardness. Meyer's index on average decreases with increasing of the speed.

The Indentation Size Effect (ISE) and the Speed of the Indenter Penetration into Test Piece

Petrík¹,

Palfy²,

Blaško³

et al. 2016

Influence of the Bending Momentum Loading of Testing Samples from the Alloy AlSi7Mg0.3 on the Surface Stress State Detected by X-ray Diffraction

Řidký¹,

Sobotka²

2016

These days are more and more posing claims for the highest quality of castings from the aluminium alloys and for the lowest weight of these castings. Thus for complex material (in this case alloy) utilization it is very important to monitor its behavior both during production (chemical composition, metallographic evaluation of the structure, observance of thermal treatments temperatures, refining and degassing of melt and so on) and also during its loading. This papers deals with the monitoring changes of stress on the testing samples surface arising from the force loading. As a loading there was a bending momentum at the testing samples (rods) from the alloy AlSi7Mg0,3 which was poured into the metal mould after the different thermal treatment methods. Bending momentum increased up to the expressive deformation of the tested sample. Results were also completed by the depth profile of the residual stresses which were measured by means of the X-ray diffraction (X-ray tensiometry analysis) namely for all thermal treatment methods. Moreover in the depth profile there was also performed the qualitative evaluation of the structure by the back-reflection Debye-Scherrer method.

Thermal Treatment Influence on the Change of Alloy EN AW-6082 Mechanical Properties

Solfronk¹,

Sobotka²,

Kolnerova³

et al. 2017

Thermal treatment of the aluminum alloys significantly affects their final mechanical properties. However, the process of such thermal treatment is influenced by many variables and the correct choice of these technological parameters is a prerequisite for achieving their required properties in the manufactured part. This paper evaluates the effect of thermal treatment conditions on the time course of hardness for EN AW-6082 alloy during artificial aging. For the experiment, the solution annealing temperature of 520°C was chosen in combination with three different holding times at this temperature and then also 3 different initial temperature of the material before cooling in water. The effect of the thermal treatment parameters was subsequently monitored by the Brinell hardness time course at 3 selected artificial aging temperatures.