Effect of Al-Ti-B Based Master Alloys on Grain Refinement and Hot Tearing Susceptibility of AZ91E Magnesium Alloy

2011 ◽  
Vol 690 ◽  
pp. 351-354 ◽  
Author(s):  
Elsayed Abdallah ◽  
Comondore Ravindran ◽  
B.S Murty
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Base Alloy ◽  
Hot Tearing ◽  
Automotive Applications ◽  
Dog Bone ◽  
Master Alloys ◽  
As Stress ◽  
Hot Tearing Susceptibility

The objective of this study was to examine the potential of Al-5Ti-1B and Al-1Ti-3B master alloys in reducing the hot tearing susceptibility of AZ91E magnesium alloy. The low penetration of magnesium alloys for structural automotive applications can be attributed to their poor castability during permanent mould casting. An improvement in the castability of magnesium alloys will result in the production of larger castings for automotive applications and a reduction in vehicle weight. The addition levels examined for both master alloys were 0.1, 0.2, 0.5 and 1.0 wt.%. The master alloys were added to the AZ91E alloy and stirred for 30 seconds. For the graphite mould castings used to observe grain refinement, the pouring and mould temperatures were 720 and 750 °C respectively. The hot tear castings were produced using a “dog bone” shaped H-13 tool steel mould. The pouring and mould temperatures were 720 and 180 °C respectively. Without master alloy addition, the base AZ91E casting had severe hot tears. The addition of Al-5Ti-1B slightly reduced hot tears while Al-1Ti-3B addition significantly reduced hot tears. The addition of Al-1Ti-3B also significantly reduced the grain size of the castings from 113 µm in the base alloy to 72 µm with 1.0 wt.% addition. The addition of Al-5Ti-1B did not lead to a reduction of hot tears because of large TiAl3 particles acting as stress risers during solidification.

scholarly journals Novel grain refinement of AZ91E magnesium alloy and the effect on hot tearing during solidfication

2021 ◽  
Author(s):  
Abdallah Elsayed
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Hot Tearing ◽  
Grain Refining ◽  
Grain Refiner ◽  
Structural Applications ◽  
Hot Tearing Susceptibility

For the A1-5Ti-1B grain refiner, the addition of 0.1 wt.% provided a 68 % reduction in grain size as compared to the unrefined AZ91E alloy at a holding time of five minutes. Grain growth restriction by TiB₂ particles was the source of grain refinement. With the addition of A1-5Ti-1B, only a small reduction in hot tearing susceptibility ws observed because large TiA1₃ particles bonded poorly with the eutectic and blocked feeding channels.The addition of 1.0 wt.% A1-1Ti-3B provided a grain size reduction of 63% as compared to the unrefined AZ91E alloy at a holding time of five minutes. The grain refinement with A1-1Ti-3B addition was attributed to a combination of TiB₂ grain growth restriction and A1B₂ nucleating sites. A significant reduction in hot tearing susceptibility was observed with A1-1Ti-3B addition as a result of a higher cooling rate and shorter local soldification time as compared to the AZ91E alloy. The reduction in hot tearing susceptibility was attributed to the good interface between eutectic and TiB₂ particles. Both grain refiners demonstrated a good resistance to fading during the holding times investigated. In addition, the AZ91E + A1-5Ti-1B and AZ91E + A1-1Ti-3B castings showed much fewer dislocation networks as compared to the untreated AZ91E casting.The development of efficient A1-Ti-B refiners can also improve castability of magnesium alloys. In addition, the fade resistant A1-Ti-B grain refiners can reduce operating costs and maintain productivity on the foundry floor. Thus, magnesium alloy with A1-Ti-B treatment have the potential for more demanding structural applications in the automobile and aerospace industries. Vehicle weight in the aerospace and automotive industries directly impacts carbon emissions and fuel efficiency. An increase in the use of lightweight materials for structural applications will result in lighter vehicles. Low density materials, such as magnesium (1.74 g/cm³) are a potential alternative to aluminium (2.70 g/cm³), to reduce component weight in structural applications.However, current magnesium alloys still do not have adequate mechanical properties and castability to meet the performance specifications of the automotive and aerospace industries. Grain refinement can significantly improve mechanical properties and reduce hot tearing during permanent mould casting. Recently, Al-Ti-B based grain refiners have shown potential in grain refining magnesium-aluminum alloys such as AZ91E. This study investigates the grain refining efficiency and fading of A1-5Ti-1B and A1-1Ti-3B in AZ91E magnesium alloy and their subsequent effect on hot tearing.The grain refiners were added at 0.1, 0.2, 0.5 and 1.0 wt.% levels. For the grain refinement and fading experiments, the castings were prepared using graphite moulds with holding times of 5, 10 and 20 minutes. For the hot tearing experiments, castings were produced representing the optimal addition level of each grain refiner. The castings were prepared using a permanent mould with pouring and mould temperatures of 720 and 180 ºC, respectively. The castings were characterized using SEM, TEM, optical microscopy and thermal analysis.

scholarly journals Novel grain refinement of AZ91E magnesium alloy and the effect on hot tearing during solidfication

2021 ◽  
Author(s):  
Abdallah Elsayed
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Hot Tearing ◽  
Grain Refining ◽  
Grain Refiner ◽  
Structural Applications ◽  
Hot Tearing Susceptibility

For the A1-5Ti-1B grain refiner, the addition of 0.1 wt.% provided a 68 % reduction in grain size as compared to the unrefined AZ91E alloy at a holding time of five minutes. Grain growth restriction by TiB₂ particles was the source of grain refinement. With the addition of A1-5Ti-1B, only a small reduction in hot tearing susceptibility ws observed because large TiA1₃ particles bonded poorly with the eutectic and blocked feeding channels.The addition of 1.0 wt.% A1-1Ti-3B provided a grain size reduction of 63% as compared to the unrefined AZ91E alloy at a holding time of five minutes. The grain refinement with A1-1Ti-3B addition was attributed to a combination of TiB₂ grain growth restriction and A1B₂ nucleating sites. A significant reduction in hot tearing susceptibility was observed with A1-1Ti-3B addition as a result of a higher cooling rate and shorter local soldification time as compared to the AZ91E alloy. The reduction in hot tearing susceptibility was attributed to the good interface between eutectic and TiB₂ particles. Both grain refiners demonstrated a good resistance to fading during the holding times investigated. In addition, the AZ91E + A1-5Ti-1B and AZ91E + A1-1Ti-3B castings showed much fewer dislocation networks as compared to the untreated AZ91E casting.The development of efficient A1-Ti-B refiners can also improve castability of magnesium alloys. In addition, the fade resistant A1-Ti-B grain refiners can reduce operating costs and maintain productivity on the foundry floor. Thus, magnesium alloy with A1-Ti-B treatment have the potential for more demanding structural applications in the automobile and aerospace industries. Vehicle weight in the aerospace and automotive industries directly impacts carbon emissions and fuel efficiency. An increase in the use of lightweight materials for structural applications will result in lighter vehicles. Low density materials, such as magnesium (1.74 g/cm³) are a potential alternative to aluminium (2.70 g/cm³), to reduce component weight in structural applications.However, current magnesium alloys still do not have adequate mechanical properties and castability to meet the performance specifications of the automotive and aerospace industries. Grain refinement can significantly improve mechanical properties and reduce hot tearing during permanent mould casting. Recently, Al-Ti-B based grain refiners have shown potential in grain refining magnesium-aluminum alloys such as AZ91E. This study investigates the grain refining efficiency and fading of A1-5Ti-1B and A1-1Ti-3B in AZ91E magnesium alloy and their subsequent effect on hot tearing.The grain refiners were added at 0.1, 0.2, 0.5 and 1.0 wt.% levels. For the grain refinement and fading experiments, the castings were prepared using graphite moulds with holding times of 5, 10 and 20 minutes. For the hot tearing experiments, castings were produced representing the optimal addition level of each grain refiner. The castings were prepared using a permanent mould with pouring and mould temperatures of 720 and 180 ºC, respectively. The castings were characterized using SEM, TEM, optical microscopy and thermal analysis.

The influence of gadolinium on Al–Ti–C master alloy and its refining effect on AZ31 magnesium alloy

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenxue Fan ◽  
Hai Hao
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Master Alloy ◽  
Cast Alloy ◽  
Az31 Magnesium Alloy ◽  
Synthesis Mechanism ◽  
Refining Effect ◽  
Master Alloys

Abstract Grain refinement has a significant influence on the improvement of mechanical properties of magnesium alloys. In this study, a series of Al–Ti–C-xGd (x = 0, 1, 2, 3) master alloys as grain refiners were prepared by self-propagating high-temperature synthesis. The synthesis mechanism of the Al–Ti–C-xGd master alloy was analyzed. The effects of Al–Ti–C-xGd master alloys on the grain refinement and mechanical properties of AZ31 (Mg-3Al-1Zn-0.4Mn) magnesium alloys were investigated. The results show that the microstructure of the Al–Ti–C-xGd alloy contains α-Al, TiAl3, TiC and the core–shell structure TiAl3/Ti2Al20Gd. The refining effect of the prepared Al–Ti–C–Gd master alloy is obviously better than that of Al–Ti–C master alloy. The grain size of AZ31 magnesium alloy was reduced from 323 μm to 72 μm when adding 1 wt.% Al–Ti–C-2Gd master alloy. In the same condition, the ultimate tensile strength and elongation of as-cast alloy were increased from 130 MPa, 7.9% to 207 MPa, 16.6% respectively.

Comparation about Refining Efficiency to Microstructure of AZ31 Magnesium Alloy for Sr Master Alloys

2015 ◽  
Vol 816 ◽  
pp. 498-503
Author(s):  
Ren Ju Cheng ◽  
Bo Liu ◽  
Bin Jiang ◽  
Su Qin Luo ◽  
Qing Shan Yang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Az31 Magnesium Alloy ◽  
Refining Efficiency ◽  
Refinement Efficiency ◽  
Master Alloys ◽  
Refinement Effect ◽  
Cast Microstructure ◽  
Better Than

In the present work, the influence of Al-Sr and Mg-Sr master alloys on the as-cast microstructure of the AZ31 magnesium alloy was investigated,and the refinement efficiencies of both master alloys were also analyzed and compared. The research results indicate that both the Al-Sr and Mg-Sr master alloys have obvious refinement effect on the as-cast microstructure of the AZ31 magnesium alloy, and the refinement efficiency of the Mg-Sr master alloys was better than that of the Al-Sr master alloys. The mechanisms for the differences of grain refinement efficiency between Al-Sr and Mg-Sr master alloys on the AZ31 magnesium alloys were also discussed.

Effects of solutionized Al–10Sr master alloys on grain refinement of AZ31 magnesium alloy

2008 ◽  
Vol 461 (1-2) ◽  
pp. 298-303 ◽  
Author(s):  
Mingbo Yang ◽  
Fusheng Pan ◽  
Renju Cheng ◽  
Aitao Tang
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Az31 Magnesium Alloy ◽  
Master Alloys

Roundness and Cylindricity Verification of Cylindrical Workpieces of Magnesium Alloys Obtained by Intermittent Dry Machining

2012 ◽  
Vol 498 ◽  
pp. 219-223
Author(s):  
B. de Agustina ◽  
N. Clavijo ◽  
M. Villeta ◽  
E.M. Rubio
Keyword(s):  
Experimental Study ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Weight Reduction ◽  
Fuel Efficiency ◽  
Machining Process ◽  
Dry Machining ◽  
Automotive Applications

Magnesium is the lightest metal used in industry, above all for aerospace and automotive applications where weight reduction allows an improvement in the fuel efficiency and reducing CO2 emission. In this work, an experimental study was carried out in order to determine with which machining process, turning or milling, are obtained cylindrical bars of magnesium alloy UNS M11917 by intermittent dry cut with improved roundness and cylindricity finish.

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