Modelling of Strain-Controlled Thermomechanical Fatigue Testing of Cast AlSi7Cu3.5Mg0.15 (Mn, Zr, V) Alloy for Different Aging Conditions
, Daniel Larouche 1,*, Francis Breton 2, Rémi Martinez 3, X.-Grant Chen 4 and Denis Massinon 5Round 1
Reviewer 1 Report
The manuscript reports fatigue test measurements along with a resulting viscoelastic model for Al alloys. As authors extensively illustrated in Introduction, Al-Cu alloys go through a few precipitation stages, and the thermomechanical behavior of Al-Cu alloys depends on precipitates as evident in Fig. 10. Also as the authors explained, the lack of microstructural information results in the opposite trend in the cyclic behavior in Fig. 9.
While the development of the proposed model is sound, it can be applied to materials with minimal changes in the microstructures. Taking into account all the microstructural evolutions may go beyond the scope of this manuscript, but the authors need to clarify to what extent the proposed model is valid.
Author Response
Please see the attachment,
Best regards,
The authors.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Thermomechanical fatigue is an important problem related to the service reliability of materials, and the research carried out by the author is of great significance.
The inadequacies of this paper are:
1 The fatigue test introduced in this paper does not give basic result data: for example, hysteresis loops under different strain amplitudes and fatigue life test data. These data are necessary for the description of fatigue characteristics of materials concerned in this paper.
2 The creep test results under different stresses are not shown in the paper, and the model parameters related to creep should be identified by referring to these tests.
3 The material's numerical modeling results corresponding to the above phenomena (hysteresis loops under different strain amplitudes and creep under different stresses) are not introduced.
4 The plastic strain rate in Eq. (2) should have been defined as non-negative, while the plastic strain in the formula can be positive or negative. The author should clearly define the two.
5 Under fatigue cyclic loading, the material may exhibit cyclic hardening or softening (as shown in Figure 8). Eq. (2) does not consider this phenomenon, and it is suggested that the author make a further explanation. In addition, for material with cyclic softening characteristics, the authors seem to should show the hysteresis loop evolving with the cycle, rather than only one loop as in Figure 5.
6 The measured cyclic hysteresis loop shown in Figure 7 is not symmetrical. Does slight plastic buckle deformation happen during compression? The author should give a concise explanation. At the same time, it seems that the temperature of the test in Figure 7 is not explained in the text.
7 In this paper, it is mentioned that there is a temperature gradient in the sample during thermal loading, but it seems that the test or estimation results of the temperature gradient of the sample at different times are not given.
8 The OP-TMF test is introduced in the paper, but it seems that the corresponding measured result like the hysteresis loop is not displayed.
Author Response
Please see the attachment,
Best regards,
The authors.
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript reported the modelling of strain-controlled thermomechanical fatigue testing of cast AlSi7Cu3.5Mg0.15 (Mn, Zr, V) alloy for different aging conditions. This is of great importance in the thermomechanical fatigue fields of Al alloys. The topic of this paper is within the scope of Metals. Several minor issues are necessary to be addressed before the paper can be accepted.
1. The introduction should be simplified. For example, in “Thermomechanical fatigue of cast aluminium alloys” section, we just see the long literature review about the thermomechanical fatigue. The key scientific issue of present paper or merit and demerit should be proposed according these contents.
2. Is the size of LCF, creep and TMF specimens designed according to the standard? Please write it.
3. Fig. 11: The failure location is close to specimen transition. Is it valid to estimate?
4. Fig. 8(a): The experimental and simulative curves are conflicting. Please give a further explanation.
5. Fig. 7: what is the meaning of mechanical in “ε mechanical”?
6. Several minor language mistakes: “line 204, a”, “line 218”, “line 417, experimental”.
Author Response
Please see the attachment,
Best regards,
The authors.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The author appropriately answered the reviewer's questions. I have no more questions and suggest that the journal Metals publish this paper.
