Effect of Ca and Sr on the compressive creep behavior of Mg–4Al–RE based magnesium alloys

Zhang, Yaocheng; Li, Yang; Dai, Jun; Ge, Jijiang; Guo, Guolin; Liu, Zhong

doi:10.1016/j.matdes.2014.06.027

Cited by 45 publications

(16 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the strength of traditional precipitation strengthening alloys, such as 2xxx, 6xxx and 7xxx alloys, can be seriously deteriorated due to the rapid coarsening of precipitates at elevated temperature (i.e., the overaging effect) [1,2]. Conversely, dispersoid strengthening is reported to be an important hardening mechanism at elevated temperature in aluminum alloys [3][4][5][6][7][8]. Therefore, developing low cost and thermally stable aluminum alloys with dispersoid precipitation that function well at elevated temperature is particularly attractive for these industries.…”

Section: Introductionmentioning

confidence: 99%

Development of Al–Mn–Mg 3004 alloy for applications at elevated temperature via dispersoid strengthening

2015

View full text Add to dashboard Cite

In this study, the potential applications of Al-Mn-Mg 3004 alloy at elevated temperature have been evaluated through the systematic study of the precipitation behavior of α-Al(MnFe)Si dispersoids and their effect on material properties during precipitation treatment and long-term thermal holding. The results demonstrate a significant dispersion strengthening effect caused by the precipitation of fine uniformly distributed dispersoids during precipitation treatment. The peak compression yield strength (YS) at 300°C of the experimental 3004 alloy can reach as high as 78 MPa due to a large volume fraction (~2.95 vol. %) of α-Al(MnFe)Si dispersoids. The dispersoids are found to be thermally stable at 300°C for up to 1000 h of holding, leading to consistently high mechanical performance and creep resistance. The superior and stable YS and creep resistance at 300°C enables the 3004 alloy to be applied to weight-sensitive applications at elevated temperatures.

show abstract

Section: Introductionmentioning

confidence: 99%

Development of Al–Mn–Mg 3004 alloy for applications at elevated temperature via dispersoid strengthening

2015

View full text Add to dashboard Cite

show abstract

“…It has also been claimed that the low creep resistance of AZ91 alloy mainly stems from the low melting temperature (735K (462°C)) of the intermetallic [67,[80][81][82][83]. Addition of RE elements [84,85] or Si [67] aiming at introducing thermally stable intermetallics improves the creep somewhat.…”

Section: Solid Solution Hardeningmentioning

confidence: 99%

“…Y in solution is much more effective than Al [1,12] when it comes to improving creep strength. 6 Many studies, e.g., [80,82,86] Zhu et al [88] and Gibson et al [76] showed that the creep strength of Mg-RE alloys increases with the content of the RE and concluded that both solid solution and precipitation hardening are major factors in the creep strength of these alloys, in decreasing order for Nd, Ce and La. Xu et al [89] showed that partly replacing Gd by Y in a Mg-Gd alloy leads to decreased number density of precipitates while still increasing the creep strength, an indication of the stronger effect of solid solution over precipitation in these alloys.…”

Section: Solid Solution Hardeningmentioning

confidence: 99%

Thermodynamics-based design of creep resistant Mg solid solutions using the Miedema scheme

Abaspour¹

View full text Add to dashboard Cite

Most current creep resistant alloy design methods for Mg alloys aim at incremental strengthening of existing alloys such as AZ91 thorough addition of ternary and quaternary elements, or alternatively through RE's additions. The most remarkable improvements has been through either Mg-Y or recently developed Mg-Gd-Y-Zr and Mg-Y-Nd-Zr alloys, although still below the strength of MgTh alloys, which are being phase out due to Th's radioactivity.Many micromechanisms proposed to account for the observed improvements in either hardness or creep strength of Mg alloys including solid solution and/or precipitation hardening, dynamic precipitation, solute dragging/solute clustering and more importantly atomic size controlled diffusivity more often than not are little more than ad-hoc, after-the-fact explanations, valid at best for the particular system under consideration. Hence, extrapolation to other alloy-systems is either not possible or contradictory. In practice, a feasible path for systematic, either precipitationhardened or creep-resistant Mg alloys, selection and design is still lacking.The aim of the present work was to use atomic level thermodynamical arguments that suggest that extending the athermal regime through short range order (SRO) is a most feasible path to increasing the creep strength of Mg alloys. Potential solutes were sorted out and ranked based on their tendency to developing SRO using the Miedema's phenomenological scheme. The predictions were corroborated by experiments involving dilute binary alloys as well as through a collection of data from the literature.Monotonic compression and stress relaxation tests were carried out on specimens of 6 cast binary alloys with (at.%) 2.5 Al, 0.6 Sn, 2.2 Zn, 0.8 Gd, 1.3 Y and 0.9 Nd, and of a similarly cast AZ91D alloy for reference. The solute concentration in the binary alloys was kept deliberately low to limit precipitation hardening effects during the testing. Compression testing was carried out at 298K (25°C), 373K (100°C) and 453K (180°C) The relative tendency or lack of it, of most solutes to develop SRO rationalizes a number of observations in current multicomponent Mg alloys while it disputes the viability of several other micromechanisms often considered.The feasibility of strengthening HPDC Mg alloys through a combination of percolating eutectics and residual solute in solution, or, more generally, age hardenable alloys through either homogeneously nucleated, coherent with the Mg matrix, precipitates, or via internally ordered precipitates mimicking Mg-Th alloy system, is also considered by making parallels with either the Al-Zn or the Al-Cu alloy systems. Examples of these approaches were discussed using data from the literature, such as experiments on alloys combining Mn and Sc to introduce order in the soft Mn precipitates, or the use of Na to provide finely dispersed, homogeneously nucleated clusters with the aim of refining the subsequent precipitation in alloys such as Mg-Sn. III Declaration by authorThis thesis is composed of my or...

show abstract

“…Unfortunately, the Mg-Zn series has the same problem as the Mg-Al series (but not the AE series), that is, poor mechanical properties at elevated temperatures which restrict their applications [2]. Recently, strontium has drawn much attention [11][12][13][14] as an important additive in Mg-based alloys for improving relatively high temperature mechanical properties. According to Baril et al [14], the micro-alloying of strontium in magnesium alloys (e.g., Mg-Zn, Mg-Al based alloys) permits to obtain superior creep performance and excellent high-temperature properties.…”

Section: Introductionmentioning

confidence: 99%

“…The reported experimental binary phase diagrams[12][13][14] of the Mg-Zn-Sr system along with the nominal compositions of key samples prepared in the present work.…”

mentioning

confidence: 96%

Experimental study of the crystal structure of the Mg15−xZnxSr3 ternary solid solution in the Mg–Zn–Sr system at 300°C

et al. 2015

View full text Add to dashboard Cite

Effect of Ca and Sr on the compressive creep behavior of Mg–4Al–RE based magnesium alloys

Cited by 45 publications

References 24 publications

Development of Al–Mn–Mg 3004 alloy for applications at elevated temperature via dispersoid strengthening

Development of Al–Mn–Mg 3004 alloy for applications at elevated temperature via dispersoid strengthening

Thermodynamics-based design of creep resistant Mg solid solutions using the Miedema scheme

Experimental study of the crystal structure of the Mg15−xZnxSr3 ternary solid solution in the Mg–Zn–Sr system at 300°C

Contact Info

Product

Resources

About