Effect of Cr content and heat-treatment on the high temperature strength of eutectic Al–Si alloys

Yang, Yuying; Zhong, Shengyi; Chen, Zhe; Wang, Mingliang; Ma, Naiheng; Wang, Haowei

doi:10.1016/j.jallcom.2015.05.167

Cited by 81 publications

(24 citation statements)

References 33 publications

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“…An increase in content of the Al3CuNi and Al9NiFe phases is also responsible for some reduction in ductility [4]. It is found that the increase of Cr content exhibits a detrimental effect on the elevated temperature tensile strength of eutectic Al-Si-Cu-Mg alloys [35]. Although Ti has a small diffusivity in Al, only a small concentration of Ti is incorporated in the precipitates [36].…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Zr-containing precipitates; a solution for significant improvement of high-temperature strength in Al-Si-Cu-Mg alloys

Rahimian

Amirkhanlou

Blake

et al. 2018

Materials Science and Engineering: A

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This work aims to reveal the valuable role of Zr in cast Al-Si-Cu-Mg alloys utilised at elevated temperatures. The Al7Si2Cu0.2Zr alloy, subjected to well-tuned heat treatment process, was benchmarked against the conventional Al7Si0.5Cu alloy. Microstructural investigation showed that the main strengthening phases in the Al7Si2Cu0.2Zr alloy are θ´, Q´, Al-Si-Cu-Zr and Al-Si-Zr precipitates. Two Zr-containing precipitates (Al-Si-Cu-Zr and Al-Si-Zr) with the size of 80-200 nm are formed during solutionising at530 °C, which can be considered as the first ageing step. Other two Cu-containing precipitates (θ´and Q´) at the size of 20 nm are formed during ageing (170 °C). Nano-sized Zr-containing precipitates are mostly exhibited elliptical morphology with coherent/semi-coherent interfaces with the α-Al matrix, making them more stable at elevated temperatures. As a result, the yield strength is improved at room temperature from 261 to 291 MPa, and the ultimate tensile strength (UTS) is improved from 282 to 335 MPa for the Al7Si2Cu0.2Zr alloy, compared with the Al7Si0.5Cu alloy. Moreover, the mechanical properties are significantly improved at elevated temperatures. The yield strength and UTS at 200 °C are 177 and 186 MPa, respectively, for the Al7Si0.5Cu alloy. But these are224 and 246 MPa, respectively, for the Al7Si2Cu0.2Zr 2 alloy. The improvement of mechanical properties at elevated temperatures is mainly attributed to the refined microstructure and the precipitation of strengthening phases containing slow-diffused Zr element to retard the precipitation coarsening. Furthermore, the addition of Cu changes the precipitates from θ´ and β´´ in the Al7Si0.5Cu alloy to θ´ and Q´ in the Al7Si2Cu0.2Zr alloy which, in turn, induce a complementary effect on the improvement of mechanical properties.

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Section: Introductionmentioning

confidence: 99%

Nanoscale Zr-containing precipitates; a solution for significant improvement of high-temperature strength in Al-Si-Cu-Mg alloys

Rahimian

Amirkhanlou

Blake

et al. 2018

Materials Science and Engineering: A

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“…2 b) alloys independent of the Er addition. All these phases are the typical compounds in the Al-Si-Cu-Ni-Mg-Fe piston alloys, as identified in the references [40,41]. With the addition of Er, the Al3ErNi2 compound forms in 2# and 3# samples at T5 state (Fig.…”

Section: Fig 1 the Dimensions For 'Dog-bone' Type Specimens (The Unitmentioning

confidence: 79%

Effect of Er Addition on the High Temperature Strength of Al-Si-Cu-Ni-Mg-Fe Piston Alloys

Li¹,

Xia²,

Wu³

et al. 2019

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In this study, the dependence of Er addition (0-0.49 wt %) on the microstructural evolution and related tensile strength at high temperature (HT) were investigated for the eutectic Al-Si piston alloys. The results showed there were intermetallic compounds of -Al3CuNi, -Al7Cu4Ni, Al4Cu2Mg8Si7, β-AlFeSi and Al3(Er, Cu, Fe) (Ni, Si) 2 identified at T5 states. Herein, the added Er element has led to the formation of the star-like and the irregular-shaped Al3(Er, Cu, Fe) (Ni, Si) 2 phase. The phase was stable which showed little change in both size and composition experienced solid solution at HT during the T6 treatment. For the HT strengths (350 oC), the T5 state alloys have higher UTSs than those at T6 state, both of which were reduced gradually with the increasing Er contents. The variation of HT strengths caused by the Er addition was explained by the microstructral evolution, namely Al3(Er, Cu, Fe) (Ni, Si)2 phase formation

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“…According to literature data [108], the presence of Cr in Al−Si cast alloys changes the morphology of the β−AlFeSi phase from the needle-like to a fishbone-like α−Al(Fe,Cr)Si phase, leading to an improvement of ultimate strength. Unknown remains the synergy of simultaneous presence of Ti, Zr, V, and Cr.…”

Section: Al−si Alloys With Micro-additions Of Zr V Ti and Crmentioning

confidence: 93%

Thermal Stability of Aluminum Alloys

Czerwiński

2020

Materials

131

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Thermal stability, determining the material ability of retaining its properties at required temperatures over extended service time, is becoming the next frontier for aluminum alloys. Its improvement would substantially expand their range of structural applications, especially in automotive and aerospace industries. This report explains the fundamentals of thermal stability; definitions, the properties involved; and the deterioration indicators during thermal/thermomechanical exposures, including an impact of accidental fire, and testing techniques. For individual classes of alloys, efforts aimed at identifying factors stabilizing their microstructure at service temperatures are described. Particular attention is paid to attempts of increasing the current upper service limit of high-temperature grades. In addition to alloying aluminum with a variety of elements to create the thermally stable microstructure, in particular, transition and rare-earth metals, parallel efforts are explored through applying novel routes of alloy processing, such as rapid solidification, powder metallurgy and additive manufacturing, engineering alloys in a liquid state prior to casting, and post-casting treatments. The goal is to overcome the present barriers and to develop novel aluminum alloys with superior properties that are stable across the temperature and time space, required by modern designs.

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Effect of Cr content and heat-treatment on the high temperature strength of eutectic Al–Si alloys

Cited by 81 publications

References 33 publications

Nanoscale Zr-containing precipitates; a solution for significant improvement of high-temperature strength in Al-Si-Cu-Mg alloys

Nanoscale Zr-containing precipitates; a solution for significant improvement of high-temperature strength in Al-Si-Cu-Mg alloys

Effect of Er Addition on the High Temperature Strength of Al-Si-Cu-Ni-Mg-Fe Piston Alloys

Thermal Stability of Aluminum Alloys

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