The Research Progress of TiB2 Impacts on the Refining Effect of Al-Ti-B Master Alloy

2014 ◽  
Vol 574 ◽  
pp. 391-395
Author(s):  
Li Mi ◽  
Jun Jun Wang ◽  
Zhi Liu Hu
Keyword(s):  
Master Alloy ◽  
Refining Process ◽  
Research Progress ◽  
Grain Refining ◽  
Grain Refiner ◽  
Standing Time ◽  
Refining Effect ◽  
Initial Nucleus ◽  
Refinement Mechanism ◽  
The Impact

Al-Ti-B master alloy is the most widely used grain refiner in the aluminum fabrication industry, while it’s refinement mechanism is not clearly understand yet. The TiB2 in Al-Ti-B master alloy is one of important phase to grain refining, which intimately related to the generation of initial nucleus, the “fading” phenomenon of refining effect declines with the increase of holding or standing time in grain refining process. Besides, TiB2 is analyzed in several studies about the “poisoning” phenomenon, a large extent weaken of refining effect when Zr, Cr, Mn etc. exists. In this article, the impact of TiB2 to the refining effect of Al-Ti-B master alloy is discussed aiming at the roles and phenomenon mentions above.

Influence of a Novel Master Alloy Addition on the Grain Refinement of Al-Si Cast Alloys

2013 ◽  
Vol 765 ◽  
pp. 311-315 ◽  
Author(s):  
Leandro Bolzoni ◽  
Magdalena Nowak ◽  
N. Hari Babu
Keyword(s):  
Grain Refinement ◽  
Master Alloy ◽  
Intermetallic Phases ◽  
Al Alloys ◽  
Grain Structure ◽  
Grain Refiner ◽  
Casting Alloys ◽  
Alloy Addition ◽  
Cast Alloys ◽  
The Impact

The grain refinement practice using Ti based chemical additions is well established for wrought Al alloys, especially in the last few decades. In the case of Al-Si casting alloys the practice of adding grain refiners and the impact on castability is not well established in industries. The main reason is the chemical instability of conventionally known Ti based grain refiner which reacts with silicon forming intermetallic phases. Recently, researchers at Brunel University have identified a novel chemical composition that can refine the grain structure of Al-Si alloys in an effective way. Over the last year, this novel grain refiner in the form of master alloy was developed and tested in various Al-Si cast alloys that are commonly used in industry. Significant grain refinement is obtained when the master alloy is added to the liquid metal prior to casting. Moreover, the grain size of the Al-Si cast alloys is observed to be less sensitive to cooling rate when the master alloy is added. In this work, the influence of addition of the master alloy on microstructural evolution of various Al-Si alloys cast under various cooling rates is presented.

Grain refining effect of Mg by novel particle cluster-containing Al–Ti–C master alloy

2015 ◽  
Vol 25 (6) ◽  
pp. 1804-1810 ◽  
Author(s):  
Xiao-teng LIU ◽  
Hai HAO ◽  
Xiao-xu ZHU ◽  
Xing-guo ZHANG
Keyword(s):  
Master Alloy ◽  
Grain Refining ◽  
Particle Cluster ◽  
Refining Effect

Effect of Grain Refiner on Microstructure of Semi-Solid A356 Aluminium Alloy

2014 ◽  
Vol 1024 ◽  
pp. 251-254 ◽  
Author(s):  
Mohd Nasir Laila Masrur ◽  
Anasyida Abu Seman ◽  
Hussain Zuhailawati
Keyword(s):  
Aluminium Alloy ◽  
Master Alloy ◽  
Optical Microscope ◽  
Grain Refining ◽  
Grain Refiner ◽  
Inclined Slope ◽  
Semi Solid ◽  
Vicker’S Microhardness ◽  
Steel Mould ◽  
A356 Aluminium Alloy

Grain refining has been studied in the semi-solid-metal (SSM) casting by addition of master alloy Al-5Ti-1B using inclined slope. A356 aluminium alloy was melted at 850 °C and poured at 660 °C on the inclined slope into the steel mould. Grain refiner was added in various percentages of 0.2%, 0.5% and 1.0% in A356 aluminium alloy melt. Microstructure and microhardness were characterized using optical microscope and Vicker’s microhardness tester. The addition of master alloy Al-5Ti-1B not only refined but also increased the globularity of the primary α-Al particles. The higher hardness was achieved with 1% addition of master alloy Al-5Ti-1B.

The Combined Effect of Modifier and Grain Refiner AlTiBSr Master Alloy on Microstructure and Porosity of Aluminum Alloys

2006 ◽  
Vol 526 ◽  
pp. 223-228 ◽  
Author(s):  
Petru Moldovan ◽  
Gabriela Popescu ◽  
Marilena Cuhutencu
Keyword(s):  
Electron Microscopy ◽  
Aluminum Alloys ◽  
Master Alloy ◽  
Aluminum Industry ◽  
New Combination ◽  
Grain Refining ◽  
Grain Refiner ◽  
Multifunctional Material ◽  
Master Alloys ◽  
Foundry Alloys

The aim of the paper is to present the influence of a new multifunctional material, a master alloy named Al-Sr-Ti-B, in aluminum foundry alloys. The Al-Sr-Ti-B master alloy represents a new combination of two master alloys, already known in aluminum industry, AlTiB and AlSr, used in treatment of aluminum alloys for grain refining and modification. As Strobloy, our master alloy contain fast dissolving SrAl4 particles and also nucleating particles as TiB2 and (Al,Ti)B2 which are important first in modification and second in grain refining of aluminum alloys. The paper presents optic and electron microscopy studies realized on AlSi7Mg alloy treated with this new multifunctional material

Grain Refinement Mechanism and Effective Nucleation Phase of Al-5Ti-1B Master Alloy

2017 ◽  
Vol 898 ◽  
pp. 1231-1235 ◽  
Author(s):  
Shun Cheng Wang ◽  
Ji Lin Li ◽  
Chun Lei Gan ◽  
Kai Hong Zheng
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Pure Aluminum ◽  
Grain Refiner ◽  
Crystal Nucleus ◽  
Master Alloys ◽  
Refinement Mechanism ◽  
Nucleation Phase ◽  
Heterogeneous Nucleus

The Al-5Ti-1B, Al-10Ti, Al-4B master alloys and TiB2 powder were applied to refine the pure aluminum, respectively. The effects of the TiAl3 phase, TiB2 particle, and AlB2 phase on the grain size of pure aluminum were compared. The grain refinement mechanism of the Al-5Ti-1B grain refiner was studied. The results showed that the TiAl3 phase was an effective heterogeneous nucleus of the α-Al grain. But the TiAl3 phase in the Al-5Ti-1B grain refiner was not the heterogeneous nucleus of the α-Al grain due to its re-melting in the Al melt. The separate TiB2 particle or AlB2 phase was not the heterogeneous nucleus of the α-Al grain. However, the TiB2 coated by the TiAl3 phase can be the effective heterogeneous nucleus of the α-Al grain. The grain refinement mechanism of the Al-5Ti-1B grain refiner can be summarized as follows: when the Al-5Ti-1B grain refiner is added into the Al melt, the TiAl3 phases are re-melted to release the Ti atoms, while the TiB2 particles are remaining in the Al melt. During the solidification of the Al melt, the Ti atoms are segregating on the surface of TiB2 particles to form the TiAl3 phases. The TiB2 particles coated by the TiAl3 phases then reacts with the Al melt to generate α-Al crystal nucleus.

Grain Refining Effect of Al-5Ti-1B Master Alloy on Microstructures and Mechanical Properties of A356 Alloy

2019 ◽  
Vol 803 ◽  
pp. 17-21 ◽  
Author(s):  
Thee Chowwanonthapunya ◽  
Chaiyawat Peeratatsuwan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Master Alloy ◽  
Mechanical Performance ◽  
A356 Alloy ◽  
Casting Process ◽  
Grain Refining ◽  
Grain Refiner ◽  
Microstructures And Mechanical Properties ◽  
Al Matrix

In this study, the structures of Al-5Ti-1B master alloy and its influence on microstructures and mechanical properties of A356 alloy were investigated. The results show that Al-5Ti-1B master alloy consisted of the uniform distribution of lump-like TiB2 and network of TiAl3 on α-Al matrix. The addition of the Al-5Ti-1B master alloy can significantly reduce the grain size of A356 alloy. The mechanical properties of A356 alloy, i.e. ultimate tensile strength, yield strength and elongation were also improved. The use of Al-5Ti-1B master alloy as a grain refiner in the casting process of A356 alloy can effectively enhance the grain refinement and thus improve the mechanical performance of A356 alloy.

Fabrication of a New Al-Ti-C Master Alloy and its Refining Effect on AZ31

2015 ◽  
Vol 833 ◽  
pp. 28-32
Author(s):  
Xiao Teng Liu ◽  
Xiao Xu Zhu ◽  
Yu Zhen Zhao ◽  
Hai Hao
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Master Alloy ◽  
Az31 Alloy ◽  
Refining Process ◽  
The Self ◽  
Grain Structure ◽  
Temperature Synthesis ◽  
Refining Effect ◽  
High Temperature Synthesis

The Al-Ti-C master alloy with excessive carbon content was prepared by the self-propagating high-temperature synthesis (SHS) in melt method. The master alloy mainly contains Al4C3 and TiC phases, which exhibits satisfactory refining effect on AZ31 alloy. With 1.5wt.% addition of the master alloy, the grain size reduced from 280 μm to 109 μm. The tensile properties are also improved with the refinement of grain structure. The ultimate tensile strength increased from 105 MPa to 156 MPa while the elongation increased from 8.4% to 13.6%. The Al4C3 particles and TiC particles play important role in the refining process due to their low disregistry with α-Mg grains.

Grain Refinement Mechanism of Al-5Ti-1B Master Alloy by Ab Initio Calculations

2014 ◽  
Vol 794-796 ◽  
pp. 746-751
Author(s):  
Han Long Zhang ◽  
Yan Feng Han ◽  
Jun Wang ◽  
Yong Bing Dai ◽  
Bao De Sun
Keyword(s):  
Master Alloy ◽  
Heterogeneous Nucleation ◽  
First Principles ◽  
Chemical Potential ◽  
Grain Refining ◽  
Ordered Structures ◽  
Solid Region ◽  
Refinement Mechanism ◽  
Solid Liquid Interface ◽  
Solid Liquid

To exactly understand the grain refining mechanism of α-Al by the Al-5Ti-1B master alloy, the structural properties of α-Al/solid-TiB2(S/S) and liquid-Al/solid-TiB2(L/S) interfaces were studied using the first-principles method. Different ordered structures were formed on the interfaces with different terminations of TiB2(0001) surface, which determines the nucleant potency of TiB2. The heterogeneous nucleation of α-Al on the B-terminated surface is frustrated by an AlB2-like structure formed at the interface. In contrast, a five-layer quasi-solid region with stacking sequence of fcc-Al (111) planes forms on the Ti-terminated TiB2(0001) surface, which is the basis of successful heterogeneous nucleation of α-Al. Moreover, when redundant Ti solute being added into the liquid Al region of Ti-terminated liquid-Al/TiB2interface, the quasi-solid Al region further extends until entire solidification. The reason for using the Al-5Ti-1B master alloy rather than TiB2powders as the commercial refiner in Al industry lies in two aspects: the excessive Ti atoms in the master alloy could guarantee sufficient Ti chemical potential to form Ti-terminated surface of TiB2, and the redundant Ti solute in inoculated melts could facilitate the growth of quasi-solid Al region at the solid/liquid interface.

Effect of Ti and Zr Composite Refiner on Microstructure and Tensile Properties of Pure Aluminum

2014 ◽  
Vol 1056 ◽  
pp. 47-51
Author(s):  
Ai Wu Yu ◽  
Cheng Gang Yang ◽  
Peng He ◽  
He Chen
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Pure Aluminum ◽  
Grain Refining ◽  
Growth Morphology ◽  
Grain Refiner ◽  
Refining Effect ◽  
Average Grain Size ◽  
Columnar Grains

This study investigated the influence of Ti and Zr grain refiner on the microstructure and tensile properties of pure aluminum. The results show that Ti and Zr composite refiner exhibit better grain-refining effect than that of Ti or Zr added alone, only adding 0.15%Ti and 0.15%Zr can positively refine the grain size and change the growth morphology from columnar grains to fine equiaxed ones. When composite adding 0.5%Ti and 0.3%Zr, the tensile strength of the alloy is increased from 43.5MPa of pure aluminum to 84.4 MPa and the average grain size is reduced to only about 62μm.

Research on a New Type Grain Refiner Refining α-Al by Adding Molten State and Diluted Al-Ti-B-RE Master Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 915-918
Author(s):  
Zheng Jun Wang
Keyword(s):  
Master Alloy ◽  
Second Phase ◽  
Grain Refining ◽  
X Ray Diffraction ◽  
Grain Refiner ◽  
X Ray ◽  
Second Phase Particles ◽  
Refining Performance ◽  
New Type ◽  
The Cost

Al-Ti-B-RE master alloy was prepared by casting of pure Ti. To improve the quality and reduce the cost of α- Al, the Al-Ti-B-RE master alloy was added to α-Al in molten and diluted state. The refining method had the advantages of shorter contact time and better refining effect. The array of the second phase particles was separated and the nucleating rate was greatly increased. Analysis and comparison of the refining effects were by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM).The refining experiment showed that the molten and diluted state Al-Ti-B-RE by oneself had better grain refining performance and had obvious advantages over Al-Ti-B in domestic.

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