scholarly journals Evolution of Microstructure during Isothermal Treatments of a Duplex-Austenitic 0.66C11.4Mn.9.9Al Low-Density Forging Steel and Effect on the Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 214
Author(s):  
Idurre Kaltzakorta ◽  
Teresa Gutierrez ◽  
Roberto Elvira ◽  
Pello Jimbert ◽  
Teresa Guraya
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Strength ◽  
Grain Boundaries ◽  
Automotive Industry ◽  
Carbide Precipitation ◽  
Water Quenching ◽  
Low Density ◽  
Evolution Of Microstructure ◽  
Kappa Carbide

In the last decades, low-density steels for forging have increasing interest in the automotive industry, and good mechanical properties are required for their real application. This paper describes the results obtained for a 0.66C11.4Mn9.9Al duplex austenitic low-density steel after applying a set of isothermal treatments at different combinations of time and temperature, aimed to promote kappa carbide precipitation, and improve the mechanical properties obtained with a water quenching treatment. The effects of the different isothermal treatments on the microstructure and on the mechanical properties have been analyzed and compared to those obtained from a quenching heat treatment. We found that isothermal treatments in the range temperature between 550–750 °C promoted the profuse precipitation of coarse kappa carbides at grain boundaries, which dramatically reduced the ductility of the alloy, whereas a traditional quenching treatment resulted in a better combination of ductility and mechanical strength.

Effect of Niobium and Heat Treatment on the Microstructure and Mechanical Properties of SAE 8620 Steel

2018 ◽  
Vol 930 ◽  
pp. 327-332
Author(s):  
José Costa de Macêdo Neto ◽  
Marcelo Duarte Vieira ◽  
Ana Emília Diniz Silva Guedes ◽  
João Evangelista Neto ◽  
Bruno Mello de Freitas ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Automotive Industry ◽  
Mechanical Resistance ◽  
Low Density ◽  
Microstructure And Mechanical Properties ◽  
Sae 8620 Steel

An interest in the search for materials with reduced thicknesses, high mechanical resistance and low density has been increasing by the industry. The addition of niobium in micro-alloyed steels in the automotive industry is an alternative for obtaining light and resistant materials. The objective of this work was to verify the influence of the niobium and the heat treatment of normalizing in the microstructure and hardness of the steel SAE 8620. Also the behavior of the cementation in the steel was studied. It was verified that the removal of the normalization heat treatment did not affect the microstructure and the hardness of the steel with the niobium in relation to the steel without niobium and normalization. The cemented layer for the steel with niobium presented a greater microhardness to the depth in relation to steel without niobium.

Characterization of Microstructure and Mechanical Properties of 6060 Aluminum Alloy Processed by ECAP

2018 ◽  
Vol 275 ◽  
pp. 81-88
Author(s):  
Monika Karoń ◽  
Marcin Adamiak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Internal Stresses ◽  
Refined Grains ◽  
Angular Pressing ◽  
Heat Treated ◽  
Evolution Of Microstructure

The purpose of this paper is to present the microstructure and mechanical behavior of 6060 aluminum alloy after intense plastic deformation. Equal Channel Angular Pressing (ECAP) was used as a method of severe plastic deformation. Before ECAP part of the samples were heat treated to remove internal stresses in the commercially available aluminium alloy. The evolution of microstructure and tensile strength were tested after 1, 3, 6 and 9 ECAP passes in annealed and non annealed states. It was found that intensely plastically deformed refined grains were present in the tested samples and exhibited increased mechanical properties. Differences were noted between samples without and after heat treatment

Precipitation Strengthening in AA7449 Aluminium Alloy: Understanding the Relationship between Microstructure, Yield Strength and Strain Hardening

2006 ◽  
Vol 519-521 ◽  
pp. 991-996 ◽  
Author(s):  
G. Fribourg ◽  
Alexis Deschamps ◽  
Yves Bréchet
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Activation Volume ◽  
Rate Sensitivity ◽  
Work Hardening Rate ◽  
Deformation Step ◽  
Evolution Of Microstructure ◽  
Step Heat Treatment ◽  
The Relationship

This paper presents a detailed study of the microstructure and mechanical properties of AA7449 alloy during the two step heat treatment leading to the industrial T7651 temper. It is first shown that reproducing the heat treatment without a deformation step as used in the T7651 industrial temper leads to 2-fold decrease of the precipitation kinetics due to the absence of dislocations, while the resulting mechanical properties (if this change in kinetics is accounted for) are very similar. The work hardening rate is shown to strongly evolve during the heat treatment, and this evolution has been correlated to the evolution of microstructure using a Kocks-Mecking-Estrin analysis. Finally, an analysis in terms of activation volume of the strain rate sensitivity allows for the determination of the dislocation / precipitate interaction in the overaged temper.

Evolution of Microstructure and Mechanical Properties of the Thixo-Diecast 319s Alloy during Heat Treatment

2013 ◽  
Vol 765 ◽  
pp. 511-515 ◽  
Author(s):  
Da Quan Li ◽  
Xiao Kang Liang ◽  
Fu Bao Yang ◽  
You Feng He ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Alloy ◽  
Grain Structure ◽  
Precipitate Size ◽  
Fine Grain ◽  
Microstructure And Mechanical Properties ◽  
Optimum Heat ◽  
Evolution Of Microstructure

The evolution of microstructure and mechanical properties during solution and ageing heat treatment process was studied in terms of a thixo-diecast impeller of 319s aluminium alloy. The cast alloy exhibited a microstructure consisting of primary uniformly distributed in α-Al globules and the eutectics. A series of heat treatment studies were performed to determine optimum heat treatment parameters, in order to achieve fine grain structure, fine silicon particles and optimal precipitate size and distribution. Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study the evolution of microstructure and mechanical properties. The results demonstrate that, the full T6 heat treatments are successfully applied to thixo-diecast 319s impellers. A two-step solution heat treatment is employed to prevent porosity due to overheating. The tensile properties of thixo-diecast 319s impellers were substantially enhanced after T6 heat treatment. The plate-shaped θ′ precipitates and lath-shaped Q′ precipitates are the most effective for precipitation strengthening.

scholarly journals Effect of Dendrite Fraction on the M23C6 Precipitation Behavior and the Mechanical Properties of High Cr White Irons

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1576
Author(s):  
Jun-Seok Oh ◽  
Young-Gy Song ◽  
Baig-Gyu Choi ◽  
Chalothorn Bhamornsut ◽  
Rujeeporn Nakkuntod ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Primary Dendrite ◽  
Carbide Precipitation ◽  
Eutectic Phase ◽  
M23c6 Carbide ◽  
Eutectic Solidification ◽  
Precipitation Behavior ◽  
Conventional Heat Treatment ◽  
High Fraction

High Cr white irons with various fractions of primary dendrite have been prepared through the modification of their chemical composition. Increasing C and Cr contents decreased the primary dendrite fraction. Eutectic solidification occurred with the phase fraction ratio of austenite: M7C3 = 2.76:1. The measured primary dendrite fractions were similar to the calculated results. ThermoCalc calculation successfully predicted fractions of M7C3, austenite, and M23C6. Conventional heat treatment at high temperature caused a destabilization of austenite, releasing it’s solute elements to form M23C6 carbide. Precipitation of M23C6 during destabilization preferentially occurred within primary (austenite) dendrite, however, the precipitation scarcely occurred within austenite in eutectic phase. Thus, M23C6 precipitation by destabilization was relatively easy in alloys with a high fraction of primary dendrite.

Experimental Study on Mechanical Properties and Microstructure of 2.25Cr1Mo0.25V Steel by the Influence of Heat Treatment and Welding

2018 ◽  
Author(s):  
Qing Li ◽  
Guangxu Cheng ◽  
Mu Qin ◽  
Zaoxiao Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Base Metal ◽  
Arc Welding ◽  
Treatment Time ◽  
Welding Process ◽  
Heat Treatment Time ◽  
Evolution Of Microstructure ◽  
Welding Metal ◽  
Submerged Arc

In this paper, the mechanical properties and microstructural changes of 2.25Cr1Mo0.25V steel under different heat treatment and welding process were investigated. The heat treatment of steel during practical processing is taken as a reference. Different heat treatment time are used to obtain samples with different condition. Automatic submerged arc welding was used to obtain welding sample. The mechanical properties of different samples are obtained by tensile test; the evolution of microstructure and precipitates of different sample with heat treatment and welding was studied on scanning electron microscopy. The experimental results show that with the increase of heat treatment time, the strength of the samples decreases and the plasticity remains nearly constant. Heat treatment also affects the precipitation of carbides; the longer the heat treatment time is, the more precipitates are. Compared with the base metal, the welding metal sample has higher strength. The amount of precipitates in welding metal is much larger than it in base metal. The research on precipitation shows that there are different kinds of precipitates which have different morphologies in welding metal.

Influence of the Pouring Temperature on the Castability and Microstructure of Elektron 21 and QE22 Magnesium Casting Alloys

2013 ◽  
Vol 197 ◽  
pp. 125-130
Author(s):  
Bartłomiej Dybowski ◽  
Robert Jarosz ◽  
Andrzej Kiełbus
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnesium Alloys ◽  
Automotive Industry ◽  
Volume Fraction ◽  
Low Density ◽  
Pouring Temperature ◽  
Casting Alloys ◽  
Magnesium Casting

Magnesium alloys are widely used in aerospace and automotive industry due to their low density, good mechanical properties and good castability. The paper presents results of the castability tests and microstructural investigations on two unmodified magnesium casting alloys, Elektron 21 and QE22. Spirals for the castability test were poured from three temperatures: 755°C, 800°C and 835°C. Volume fraction of eutectic regions and grain size in both alloys were quantitatively evaluated. Castability increased with increasing pouring temperature. Quantity of eutectics and grain size did not show straight correlation with pouring temperature.

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