Q2. What is the cyclic strain curve for alloy 6082?
For alloy 6082, as the cyclic curve lies below the monotonic curve, cyclic softening occurs at low axial strain amplitudes up to 0.82%, while for strain amplitudes higher than 0.82% the alloy cyclically hardens.
Q3. What are the main objectives of the fatigue process study?
In addition to the characterisation of the cyclic stress–strain response, quantitative information on resistance to crack initiation and growth are of primary importance.*
Q4. What is the dispersoid phase of alloy 6082?
The dispersoid phase is composed of spherical and rod shaped particles, rich in Mn and containing other alloying elements such as Si and Cr, dispersed uniformly in the matrix [7].
Q5. What is the main reason for the dislocation structure of alloy 6082?
As a result of the dominating effect of the precipitates, which act as strong obstacles to dislocation motion, the dislocation/dislocation interactions are less important and three-dimensional dislocation structures, which are typical of wavy-slip materials, cannot be formed.
Q6. How was the strain hardening exponent determined?
The strain hardening exponent and strength coefficient were determined by plotting the stable stress amplitude against the axial plastic strain amplitude on a logarithmic scale.
Q7. What is the cyclic hardening rate for the 6082 alloy?
the softening rate (decrease rate of the stress amplitude) with strain cycles increases as the strain range decreases.
Q8. What is the purpose of this work?
The present work intends to analyse the microstructure influence, namely the dispersoid content, on the AlMgSi alloys response to cyclic deformation behaviour.
Q9. What was the purpose of the low-cycle fatigue tests?
Low-cycle fatigue tests were performed in a servohydraulic, closed-loop mechanical test machine with 100 kN capacity, interfaced to a computer for machine control and data acquisition.
Q10. Why does alloy 6082 have higher fatigue resistance?
As expected, due to the lower monotonic properties when compared to alloy 6082, alloy 6060 has higher fatigue properties for very high strain amplitudes (2N 6 100), but lower fatigue resistance for strain amplitudes less than approximately 2%.
Q11. What is the main requirement for the behaviour of the particle/dislocation interaction in multiple phase?
Christ and Mughrabi [6] have shown that an important requirement for Masing-type behaviour in multiple-phase materials is that the particle/dislocation interaction is of minor importance for plastic deformation compared to dislocation interactions.
Q12. What is the cyclic behaviour of alloy 6082?
From the cyclic deformation behaviour of two AlMgSi alloys with different chemical composition, thefollowing concluding remarks can be drawn: 1. Cyclic softening and hardening for axial strain amplitudes respectively lower and higher than 0.82%, were observed for alloy 6082-T6, whereas alloy 6060-T6 presented stable cyclic behaviour.
Q13. What was the important change of cyclic hardening during the early cycles of loading?
The most important changes of cyclic hardening were achieved during the early cycles ofloading, representing approximately to 1% of the fatigue life.
Q14. What is the main reason for the fatigue crack growth in AlMgSi alloys?
Several works have reported that fatigue crack growth in AlMgSi alloys can be highly influenced by the dispersoid content due to Mn or Cr being present [7,8].
Q15. What is the purpose of the study?
One of the essential goals in the fatigue process study is the prediction of the fatigue life of a structure or machine component subjected to a given stress–time history.