Improved grain refinement in aluminium alloys by re-precipitated TiB2 particles

2022 ◽  
pp. 131657
Author(s):  
Lili Zhang ◽  
Hongxiang Jiang ◽  
Jie He ◽  
Jiuzhou Zhao
Keyword(s):  
Grain Refinement ◽  
Aluminium Alloys ◽  
Tib2 Particles

scholarly journals Investigation on the Microstructure of ECAP-Processed Iron-Aluminium Alloys

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 219
Author(s):  
Bernd-Arno Behrens ◽  
Kai Brunotte ◽  
Tom Petersen ◽  
Roman Relge
Keyword(s):  
Grain Refinement ◽  
Aluminium Alloys ◽  
Aluminium Content ◽  
Microstructure Development ◽  
Chamber Furnace ◽  
Fine Grained ◽  
Angular Pressing ◽  
Ecap Process ◽  
Average Grain Size ◽  
Forming Temperature

The present work deals with adjusting a fine-grained microstructure in iron-rich iron-aluminium alloys using the ECAP-process (Equal Channel Angular Pressing). Due to the limited formability of Fe-Al alloys with increased aluminium content, high forming temperatures and low forming speeds are required. Therefore, tool temperatures above 1100 °C are permanently needed to prevent cooling of the work pieces, which makes the design of the ECAP-process challenging. For the investigation, the Fe-Al work pieces were heated to the respective hot forming temperature in a chamber furnace and then formed in the ECAP tool at a constant punch speed of 5 mm/s. Besides the chemical composition (Fe9Al, Fe28Al and Fe38Al (at.%—Al)), the influences of a subsequent heat treatment and the holding time on the microstructure development were investigated. For this purpose, the average grain size of the microstructure was measured using the AGI (Average Grain Intercept) method and correlated with the aforementioned parameters. The results show that no significant grain refinement could be achieved with the parameters used, which is largely due to the high forming temperature significantly promoting grain growth. The holding times in the examined area do not have any influence on the grain refinement.

Grain Refinement and Hot Tearing of Aluminium Alloys - How to Optimise and Minimise

2009 ◽  
Vol 630 ◽  
pp. 213-221 ◽  
Author(s):  
Mark Easton ◽  
David H. StJohn ◽  
Lisa Sweet
Keyword(s):  
Grain Refinement ◽  
Aluminium Alloys ◽  
Hot Tearing ◽  
Key Factors ◽  
Grain Refiner ◽  
Factors Affecting ◽  
Equiaxed Grains

Grain refinement and hot tearing are important key factors affecting the quality of castings. There have been substantial advances in the understanding of both of these phenomena over the last two decades. The paper discusses strategies for obtaining the lowest cost grain refiner addition and provides an explanation for how the refinement of equiaxed grains leads to a reduction in hot tear susceptibility. However, it also provides a warning that adding more grain refiner may not be better for reducing hot tear susceptibility. Alloy factors affecting hot tearing are also discussed. Finally, a list of six key considerations is provided to help casthouse and foundry engineers when trying to optimise grain refinement and reduce hot tearing.

Mechanical Properties and Wear Behavior of Aluminum Grain Refined by Ti and Ti+B

2019 ◽  
Vol 7 (1) ◽  
pp. 1-19
Author(s):  
Ahmad Omar Mostafa
Keyword(s):  
Tensile Properties ◽  
Grain Refinement ◽  
Wear Behavior ◽  
Industrial Process ◽  
Solid Solution Hardening ◽  
Coarse Grained ◽  
Wear Behaviour ◽  
Pull Out ◽  
Master Alloys ◽  
Tib2 Particles

Grain refinement, by adding master alloys, is an important industrial process for aluminum casting operations. In this work, microstructure, microhardness, tensile properties, surface roughness and wear behavior of Al and both Al-0.15Ti and Al-0.05Ti-0.01B microalloys were investigated. The addition of Ti and B to pure Al reduced the grain size by 83%. The grain refinement effect was due to the presence of Al3Ti and TiB2 particles, which activated the columnar-to-equiaxed transition and improved both microhardness and tensile properties. The presence of both Al3Ti and TiB2 particles was confirmed using thermodynamic calculations. Average microhardness values increased form 39 HV for pure Al to 95 and 76 HV for Al-Ti and Al-Ti-B microalloys, respectively, by solid solution hardening. The enhanced wear behaviour of Al was due to the coarse-grained structure where the plastic deformation mechanism took place. Whereas, grain pull-out dominated the wear behavior of fine-grained specimens. It was concluded that the material with a smooth surface has high friction coefficient and low wear rate.

Aluminium grain refinement by Ti(C, N) nanoparticles additions: principles, advantages and drawbacks

2019 ◽  
Vol 116 (2) ◽  
pp. 212 ◽  
Author(s):  
Wanpeng Li ◽  
Jian Mao ◽  
Jie Feng
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloy ◽  
Grain Refinement ◽  
Aluminium Alloys ◽  
High Hardness ◽  
Ceramic Particle ◽  
High Melting Point ◽  
The Poor ◽  
Addition Amount ◽  
Thermal And Chemical Stability

Ti(C, N) is a ceramic particle with high melting point, high hardness, high thermal and chemical stability. And incorporated Ti(C, N) particles is demonstrated to refine the grain and improve the mechanical properties of aluminium and its alloys. In this article, effects of the addition amount of Ti(C, N) particles on grain refinement and mechanical properties of aluminium alloy are reviewed, and the mechanisms of aluminium alloy refined by Ti(C, N) are described. In addition, due to the poor wettability of Ti(C, N) nanoparticles with aluminium alloy melt and the large specific surface area of Ti(C, N) nanoparticles, the Ti(C, N) nanoparticles are prone to aggregate in molten aluminium, which severely limits the application of Ti(C, N) in aluminium alloy. And effective approaches to improving the wettability of Ti(C, N) nanoparticles refine aluminium alloys are provided.

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