Creep-fatigue behaviour of aluminum alloy-based metal matrix composite

Abstract

Metal Matrix Composite (MMC) represents a valuable option as structural material for different type of structures and components. Despite this they struggle to become widely adopted due to expensive manufacturing process and complex microstructural behaviour. When subjected to cyclic load conditions the structural response of MMC is not trivial, and becomes even more difficult when high temperature load is involved. Different failure mechanisms would happen and they are originated by the different material properties between the fibre and surrounding matrix. Among all, the mismatch of thermal expansion coefficient is recognized to be the dominant one. The significantly differing coefficients of thermal expansion between ceramic and metal give rise to micro thermal stresses, which enhance the initiation of matrix micro cracks. Their performance under varying load and high temperature is complex, and hence it is difficult to have a clear understanding of the structural responses, especially when fatigue and creep damages become the main failures of MMCs. To improve current understanding of the relationship between creep fatigue interaction of MMCs, the history of thermal and mechanical loading, and the creep dwell period, a highly accurate but robust direct simulation technique on the basis of the Linear Matching Method (LMM) framework has been proposed in this paper, and been applied to model the fatigue and creep behaviour of MMCs. A homogenised FE model is considered in all analyses, which consist of continuous silicon carbide fibres embedded in a square 2024T3 aluminium alloy matrix array. Various factors that affect creep and fatigue behaviours of composites are analysed and discussed, including effects of the applied load level, dwell period and temperature on the MMC's performance. The effects of reversed plasticity on stress relaxation and creep deformation of MMC are investigated, and the behaviours of cyclically enhanced creep and elastic followup are presented. A detailed study of the creep ratchetting mechanism is also performed with the concentration on the impact of temperature and different loading conditions. The accuracy of the proposed method has been verified by detailed incremental finite element analyses using the commercial finite element solver Abaqus. Such verifications further improve the understanding of the failure mechanisms identified and discussed in this work.

Creep-fatigue and cyclically enhanced creep mechanisms in aluminium based metal matrix composites

“…In order to calculate the steady-state cycle response of a structure subjected to an arbitrary cyclic load history, a numerical procedure based on the minimization process of ( ) Chen and Ponter, 2006) and further tested (Barbera et al, 2016a;Gorash and Chen, 2013). This function is related to a class of kinematic admissible strain rate c i j ε& , defined for a L total number of loading instances.…”

“…In order to perform an accurate and efficient analysis the Linear Matching Method (LMM) is used in this work, which has been demonstrated to be capable of providing solutions for different classes of problems (Chen, 2010;Chen and Ponter, 2010;Giugliano et al, 2017;Giugliano and Chen, 2016;Gorash and Chen, 2013;Xuanchen Zhu, 2017). Recently the extended LMM Direct Steady Cyclic Analysis (eDSCA) has been adopted by the authors to perform a preliminary study on the creep and fatigue response of a MMCs unit cell (Barbera et al, 2016a), further demonstrating the method's applicability. Although the numerical results presented require extensive experimental verifications before they can be generally adopted, the features were chosen on the basis of the reasonableness of their prediction in several cases where they could be anticipated with some confidence (EDF Energy, 2014).…”

“…A 3 (0.5, 3.5), which represent shakedown for both the circular cross-section and the elliptical cross-section and reverse plasticity for the square cross-section when the applied cyclic loading condition does not have the hold time t ∆ ( Figure.3 of (Giugliano et al, 2017)). By introducing a high temperature dwell time as shown in Figure 4b, creep enhanced plasticity may occur (Barbera et al, 2016a) as discussed in section 1. In order to explore the influence of the dwell time on the steady-state behaviour of MMCs, each load point is investigated for three different dwell times i.e.…”

“…The effects of pure thermal fatigue with constant off-axis mechanical load (Chen and Ponter, 2005;Giugliano et al, 2017;Giugliano and Chen, 2016;Jansson et al, 1994;Jansson and Leckie, 1992;Ponter and Leckie, 1998a, b) and thermo-mechanical fatigue (TMF) with hold time (Barbera et al, 2016a;Bettge et al, 2007;Halford et al, 2000;Hertz-Clemens et al, 2002;Mirdamadi and Johnson, 1996;Mondali et al, 2005;Nicholas et al, 1996;Rutecka et al,…”

Cyclic plasticity and creep-cyclic plasticity behaviours of the SiC/Ti-6242 particulate reinforced titanium matrix composites under thermo-mechanical loadings

“…Validity and applicability of the LMM framework have been also acknowledged by a variety of commercial industry partners [25][26][27], in particular the LMM DSCA method has been selected by R5 research programme of EDF energy to the commercial standard [9]. In particular for the composite materials, the eDSCA was employed to analyse the cyclic creep and plastic behaviours [28][29][30]. Based on the reliability, the LMM eDSCA method is adopted for the numerical analysis in the present work.…”