A И-Shaped Curve of Hot Tearing Susceptibility in Magsimal®-59-Based Alloys

2022 ◽  
Vol 327 ◽  
pp. 98-104
Author(s):  
Bo Hu ◽  
De Jiang Li ◽  
Xiao Qin Zeng
Keyword(s):  
Liquid Fraction ◽  
Ternary Eutectic ◽  
Hot Tearing ◽  
Freezing Range ◽  
Eutectic Liquid ◽  
Si Content ◽  
Constrained Rod Casting ◽  
Hot Tearing Susceptibility

The hot tearing susceptibility of Al-6Mg-xSi (x = 0-6.0 wt.%) alloys was studied using constrained rod casting. Addition of Si content resulted in double ternary eutectic reactions and then changed the freezing range and eutectic liquid fraction greatly, which made the hot tearing susceptibility show a И-curve with the increasing of Si content. The И-curve was obviously different from the λ-curve that supported by most researchers.

Hot Tearing Susceptibility and Fluidity of Semi-Solid Gravity Cast Al-Cu Alloy

2006 ◽  
Vol 116-117 ◽  
pp. 76-79 ◽  
Author(s):  
J. Wannasin ◽  
David Schwam ◽  
J.A. Yurko ◽  
C. Rohloff ◽  
G. Woycik
Keyword(s):  
Liquid State ◽  
Copper Alloys ◽  
High Strength ◽  
Hot Tearing ◽  
Gravity Casting ◽  
Aluminum Copper Alloys ◽  
Semi Solid ◽  
High Superheat ◽  
Constrained Rod Casting ◽  
Hot Tearing Susceptibility

Aluminum-copper alloys offer both high strength and excellent ductility suitable for a number of automotive applications to reduce vehicle weight; however, the alloys are difficult to cast because of their tendency for hot tearing. In this work, semi-solid gravity casting of an aluminum-copper alloy, B206, was conducted in constrained rod casting molds to study the feasibility of using the process to reduce or eliminate hot tearing. To demonstrate the feasibility of gravity casting of the metal slurries, a fluidity test was also conducted. Results show that the hot tearing susceptibility of the aluminum-copper B206 alloy cast in semi-solid state is lower than those cast in liquid state with high superheat temperatures. The grain size of the semi-solid cast Al-Cu samples appears to be finer than those cast in liquid state with high superheat temperatures. In addition, the metal slurries had sufficient fluidity to fill the molds even with low gravity pressures. The results suggest that semi-solid gravity casting is a feasible process to help reduce hot tearing.

scholarly journals Influences of Y Additions on the Hot Tearing Susceptibility of Mg-1.5wt.%Zn Alloys

2013 ◽  
Vol 765 ◽  
pp. 306-310 ◽  
Author(s):  
Zhi Wang ◽  
Yuan Ding Huang ◽  
Amirthalingam Srinivasan ◽  
Zheng Liu ◽  
Karl Ulrich Kainer ◽  
...  
Keyword(s):  
Grain Size ◽  
Data Acquisition System ◽  
Hot Tearing ◽  
Mould Temperature ◽  
Crack Volume ◽  
Coarse Microstructure ◽  
Constrained Rod Casting ◽  
Equiaxed Grain ◽  
Zn Alloys ◽  
Hot Tearing Susceptibility

The influences of Y (0.2, 2 and 4 wt.%) additions on the hot tearing behaviour of Mg‑1.5Zn alloys were investigated using a constrained rod casting (CRC) apparatus equipped with a load cell and data acquisition system. The initiation of hot tearing was monitored during CRC experiments. It corresponds to a drop in load on the hot tearing curves. The experimental results indicate that, the hot tearing susceptibility defined by the total crack volume, which was measured by the wax penetration method, decreases with increasing the content of Y at a mould temperature of 250 °C. The reduced susceptibility is attributed to the effect of Y on the solidification behaviour: it shortens the freezing range and reduces the grain size. The highest susceptibility is observed for Mg-1.5Zn-0.2Y alloy. It is caused by its coarse microstructure and relatively larger solidification range. In contrast, the lowest susceptibility is observed for Mg-1.5Zn-4Y alloy with a small equiaxed grain microstructure. In addition, the healing of hot cracks by the subsequent refilling of the remained liquid at the later stage of solidification is also beneficial for the alleviation of hot tearing susceptibility in Mg-1.5Zn-4Y alloy.

Hot Tearing Evaluation and Contraction Behaviors of Four AA7xxx Alloys

2015 ◽  
Vol 817 ◽  
pp. 21-26 ◽  
Author(s):  
Qing Ling Bai ◽  
Jun Cheng Liu ◽  
Yue Li ◽  
Hong Xiang Li ◽  
Qiang Du ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Hot Tearing ◽  
Thermal Contraction ◽  
Solidification Range ◽  
Complex Interactions ◽  
Zn Content ◽  
Constrained Rod Casting ◽  
Hot Tearing Susceptibility

The hot tearing susceptibilities (HTS) of some AA7×××alloys, AA7050, AA7055, AA7085 and AA7022 were evaluated with constrained rod casting (CRC). Thermal contraction behaviors during solidification were measured as well in a T-shaped setup. The results showed that alloys with HTS from high to low were AA7055, AA7085, AA7050 and AA7022. Zn content in 7××× aluminum alloys seemed to play a major role with respect to the HTS index. Remarkable differences could be seen on thermal contraction behaviors within solidification range for each alloy. The rate and amount of thermal contraction for AA7055 was most prominent, followed by AA7085 and AA7050, while contraction curve of AA7022 was very flat together with least amount of thermal contraction. There was a well consistency between the amount of thermal contraction and HTS. Despite complex interactions of many variables in the formation of hot tear, thermal contraction behaviors within solidification range could give a quick evaluation of hot tearing susceptibility.

A Critical Conception of Hot-Tearing Susceptibility: Shape Casting with Wrought Aluminum Alloys

2021 ◽  
Author(s):  
Mohammad Pourgharibshahi ◽  
Hassan Saghafian ◽  
Mehdi Divandari ◽  
Farrokh Golestannejad
Keyword(s):  
Aluminum Alloys ◽  
Hot Tearing ◽  
Wrought Aluminum Alloys ◽  
Wrought Aluminum ◽  
Hot Tearing Susceptibility

scholarly journals Effect of Returnable Material in Batch on Hot Tearing Tendency of AlSi9Cu3 Alloy

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1583
Author(s):  
Justyna Kasińska ◽  
Marek Matejka ◽  
Dana Bolibruchová ◽  
Michal Kuriš ◽  
Lukáš Širanec
Keyword(s):  
Raw Materials ◽  
Qualitative Evaluation ◽  
Hot Tearing ◽  
Material Content ◽  
Negative Effect ◽  
Increased Sensitivity ◽  
Materials Used ◽  
Shape Complexity ◽  
Tear Propagation ◽  
Hot Tearing Susceptibility

The main reason for the use of returnable material, or recycled alloys, is a cost reduction while maintaining the final properties of the casting. The casting resulting quality is directly related to the correct ratio of commercial grade alloy and alloy made by remelting the returnable material in the batch. The casting quality is also affected by the purity of the secondary raw materials used, the shape complexity and the use of the casting itself. The presented article focuses on the effect of increasing the returnable material content in the batch on the hot tearing susceptibility of AlSi9Cu3 alloy. Hot tears are a complex phenomenon that combines metallurgical and thermo-mechanical interactions of the cast metal. Hot tearing susceptibility was evaluated on the basis of quantitative (HTS — hot tearing susceptibility index) and qualitative evaluation. The negative effect of returnable material in the batch was already manifested at a 20% content in the batch. The critical proportion of the returnable alloy in the batch can be stated as 50%. The alloy with a 50% returnable material content manifested insufficient results of the HTS index and qualitative evaluation, which means increased sensitivity to tearing. The negative effect of returnable material and the increased sensitivity were also confirmed in the evaluation of the fracture surface and hot tear profile. The microstructure of alloys with 50% and higher proportion of returnable material was characterized by a higher amount of iron phases (mainly Al5FeSi), whose sharp ends acted as critical regions of hot tearing and subsequent hot tear propagation, which had a major impact on the increase in hot tearing susceptibility.

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.

Effect of Silicon on the Microstructure, Tensile Properties and Hot Tearing Susceptibility of AZ91E Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 3046-3051
Author(s):  
Comondore Ravindran ◽  
Sophie Lun Sin
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Room Temperature ◽  
Hot Tearing ◽  
Chinese Script ◽  
Az91 Alloy ◽  
Solidification Behavior ◽  
Last Stage ◽  
Hot Tearing Susceptibility

This Research Focused on Studying the Effect of Silicon on the Hot Tearing Susceptibility of Permanent Mould Cast AZ91E Magnesium Alloy. Varying Amounts of Silicon (0.5, 1.0 and 1.5 Wt.%) Were Added to AZ91E in the Form of an Al-53 Wt.% Si Master Alloy. the Microstructure, Grain Size and Solidification Behavior of each Alloy Were Characterized and Related to their Tensile Properties and Hot Tearing Susceptibility. the Results Showed that the Tensile Strength and the Elongation of AZ91 Alloy Decreased with the Addition of Silicon at Room Temperature, due to the Formation of Chinese Script Mg2si Particles. however, Silicon Significantly Reduced the Hot Tearing Susceptibility of AZ91E. this Was Attributed to the Reduction of the Grain Size and the Decreased Freezing Range of AZ91E, which Contributed to Improve the Interdendritic Feeding during the Last Stage of Solidification.

Failure Analysis and Hot Tearing Susceptibility of Stainless Steel CF3M

2018 ◽  
Vol 13 (1) ◽  
pp. 166-179
Author(s):  
Dheeraj S. Bhiogade ◽  
Sanjay M. Randiwe ◽  
Abhaykumar M. Kuthe
Keyword(s):  
Stainless Steel ◽  
Failure Analysis ◽  
Hot Tearing ◽  
Hot Tearing Susceptibility

Effect of Cu on the Hot Tearing Susceptibility of Al–6Zn–2.5Mg–xCu Alloy

2020 ◽  
Author(s):  
Yongqiang Chen ◽  
Zheng Liu ◽  
Shimeng Liu ◽  
Hui Guo ◽  
Jia Liu ◽  
...  
Keyword(s):  
Hot Tearing ◽  
Hot Tearing Susceptibility
Sign in / Sign up

Export Citation Format

Share Document