Study on edge cracking and texture evolution during 150°C rolling of magnesium alloys: The effects of axial ratio and grain size

2012 ◽  
Vol 510 (1) ◽  
pp. 15-25 ◽  
Author(s):  
M. Pekguleryuz ◽  
M. Celikin ◽  
M. Hoseini ◽  
A. Becerra ◽  
L. Mackenzie
Keyword(s):  
Grain Size ◽  
Magnesium Alloys ◽  
Texture Evolution ◽  
Axial Ratio ◽  
Edge Cracking

scholarly journals Mean Field Analysis of Orientation Selective Grain Growth Driven By Interface-Energy Anisotropy

1994 ◽  
Vol 343 ◽  
Author(s):  
J. A. Floro ◽  
C. V. Thompson
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Growth ◽  
Texture Evolution ◽  
Mean Field ◽  
Orientation Distribution ◽  
Interface Energy ◽  
Abnormal Grain Growth ◽  
Field Analysis ◽  
Energy Anisotropy

ABSTRACTAbnormal grain growth is characterized by the lack of a steady state grain size distribution. In extreme cases the size distribution becomes transiently bimodal, with a few grains growing much larger than the average size. This is known as secondary grain growth. In polycrystalline thin films, the surface energy γs and film/substrate interfacial energy γi vary with grain orientation, providing an orientation-selective driving force that can lead to abnormal grain growth. We employ a mean field analysis that incorporates the effect of interface energy anisotropy to predict the evolution of the grain size/orientation distribution. While abnormal grain growth and texture evolution always result when interface energy anisotropy is present, whether secondary grain growth occurs will depend sensitively on the details of the orientation dependence of γi.

The Influence of Section Thickness on Microstructure of Elektron 21 and QE22 Magnesium Alloys

2012 ◽  
Vol 191 ◽  
pp. 145-150 ◽  
Author(s):  
Michał Stopyra ◽  
Robert Jarosz ◽  
Andrzej Kiełbus
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Magnesium Alloys ◽  
Statistical Methods ◽  
Wall Thickness ◽  
Light Microscope ◽  
Volume Fraction ◽  
Grain Structure ◽  
Section Thickness ◽  
Gating System

The paper presents analysis of section thickness’ influence on microstructure of Elektron 21 and QE22 magnesium alloys in the form of a stepped casting test. Solid solution grain size and volume fraction of eutectic areas were measured using light microscope and sterological methods. The results showed the significant increase of grain size caused by wall thickness and its slight decrease connected with the distance beetwen analysed section and the gating system. This relationship was confirmed using statistical methods. QE22 alloy demonstrated finer grain structure than Elektron 21 alloy as well as lesser susceptibility of grain size to solidification conditions

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.

Influence of Diffusion Bonding for Superplasticity Magnesium Alloys with the Fore and Post Treatment

2007 ◽  
Vol 551-552 ◽  
pp. 169-172
Author(s):  
Yan Dong Yu ◽  
C.W. Wang
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Surface Treatment ◽  
Magnesium Alloys ◽  
Diffusion Bonding ◽  
Ageing Time ◽  
Post Treatment ◽  
Ageing Temperature ◽  
Experiment Study ◽  
Shearing Strength

Influence of surface treatment to diffusion bonding before joining was analyzed during the process of magnesium alloys diffusion bonding. We processed diffusion bonding by using ZK60 rolling superplasticity magnesium alloy sheets with thickness 1.5mm and grain size 8.9$m. Joint was carried out ageing strengthening by experiment study to increase its shearing strength. Ageing strengthening performance was researched under ageing temperature 150-190 °C and the ageing time 6-48h. The results showed: diffusion bonding joints’ shearing strength had enhanced in some degrees and reached 86% of basal strength when the ageing temperature is 160 °C and the ageing time is 24h. It showed that the magnesium alloy joint’s strength could be greatly improved by ageing strengthening.

scholarly journals The Effect of Ultra-Fast Heating on the Microstructure, Grain Size and Texture Evolution of a Commercial Low-C, Medium-Mn DP Steel

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 877 ◽  
Author(s):  
Alexandros Banis ◽  
Eliseo Hernandez Duran ◽  
Vitaliy Bliznuk ◽  
Ilchat Sabirov ◽  
Roumen H. Petrov ◽  
...  
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Rapid Heating ◽  
Texture Evolution ◽  
Heating Time ◽  
Manganese Steel ◽  
Low Carbon ◽  
Fast Heating ◽  
Suitable Alternative ◽  
Heated Sample

The effect of ultra-fast heating on the microstructures of steel has been thoroughly studied over the last year as it imposes a suitable alternative for the production of ultra high strength steel grades. Rapid reheating followed by quenching leads to fine-grained mixed microstructures. This way the desirable strength/ductility ratio can be achieved while the use of costly alloying elements is significantly reduced. The current work focuses on the effect of ultra-fast heating on commercial dual phase grades for use in the automotive industry. Here, a cold-rolled, low-carbon, medium-manganese steel was treated with a rapid heating rate of 780 °C/s to an intercritical peak temperature (760 °C), followed by subsequent quenching. For comparison, a conventionally heated sample was studied with a heating rate of 10 °C/s. The initial microstructure of both sets of samples consisted of ferrite, pearlite and martensite. It is found that the very short heating time impedes the dissolution of cementite and leads to an interface-controlled α → γ transformation. The undissolved cementite affects the grain size of the parent austenite grains and of the microstructural constituents after quenching. The final microstructure consists of ferrite and martensite in a 4/1 ratio, undissolved cementite and traces of austenite while the presence of bainite is possible. Finally, it is shown that the texture is not strongly affected during ultra-fast heating, and the recovery and recrystallization of ferrite are taking place simultaneously with the α → γ transformation.

The effects of grain size and heat treatment on the deformation heterogeneities and fatigue behaviors of GW83K magnesium alloys

2019 ◽  
Vol 754 ◽  
pp. 246-257 ◽  
Author(s):  
Jipeng Pan ◽  
Liming Peng ◽  
Penghuai Fu ◽  
Haiming Zhang ◽  
Jiashi Miao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Magnesium Alloys
Sign in / Sign up

Export Citation Format

Share Document