Effect of Direct Chill Casting Speed and Heat Treatment on Microstructure and Mechanical Properties of Al-13.9%Mg2Si Composite

2016 ◽  
Vol 877 ◽  
pp. 15-19
Author(s):  
Dong Tao Wang ◽  
Hai Tao Zhang ◽  
Ke Qin ◽  
Xing Han ◽  
Bo Shao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Casting Speed ◽  
Solution Heat Treatment ◽  
Casting Process ◽  
Direct Chill ◽  
Round Shape ◽  
Sharp Edges ◽  
Dc Casting

The aim of this work is to investigate the effect of different casting speed in DC casting process and solution heat treatment of in situ Al-13.9%Mg2Si composite. The increasing of DC casting speed not only makes primary Mg2Si distribute more uniform and restricts segregation of primary Mg2Si particles, but also it reduces primary Mg2Si particle size. The DC casting speed significantly alter the eutectic Mg2Si phase from fibrous to fine dot-like and eutectic phase refines effectively. The results obtained from mechanical testing demonstrated that the increasing of DC casting speed intensifies both hardness and tensile strength values. Then, the billet were subjected to solutionizing at 500oC for holding time of 4h followed by quenching. The results indicate that the morphology of both primary and eutectic Mg2Si changes after heat treatment. Solutionizing leads to the dissolution of the Mg2Si particles and changes morphology from sharp edges to round shape. After solution heat treatment, tensile strength and elongation increase to 238.8MPa and 13.5%.

Evolution of the Retrogression and Reaging Treatment on Microstructure and Properties of Aluminum Alloy (Al-Zn-Mg-Cu)

2014 ◽  
Vol 925 ◽  
pp. 258-262 ◽  
Author(s):  
Haider T. Naeem ◽  
Khairul R. Ahmad ◽  
Kahtan S. Mohammad ◽  
Azmi Rahmat
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
Casting Process ◽  
Direct Chill ◽  
Cu Alloys ◽  
Treatment Conditions ◽  
Retrogression And Reaging ◽  
Aa 7075 ◽  
Dc Casting

In this study the evolution of the retrogression and reaging (RRA) heat treatment process on microstructure and mechanical properties of AA 7075 Al-alloys which produced by semi-direct chill (DC) casting process were investigated. Al-Zn-Mg-Cu alloys were homogenized at different heat treatment conditions, aged at 120°C for 24 h (T6), and retrogressed at 180°C for 30 min then re-aged at 120°C for 24 h (RRA). The results showed that this three-step process of the heat treatments, the mechanical properties of alloys was substantially improved. The highest ultimate tensile strength and Vickers hardness attained for the retrogression and re-aging about 530 MPa and 223 HV respectively. The precipitation strengthening is responsible about improve the strength under impact the retrogression and re-aging process.

scholarly journals Melt Conditioned Direct Chill (MC-DC) Casting and Extrusion of AA5754 Aluminium Alloy Formulated from Recycled Taint Tabor Scrap

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2711 ◽  
Author(s):  
Kawther Al-Helal ◽  
Jayesh B. Patel ◽  
Geoff M. Scamans ◽  
Zhongyun Fan
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Casting Process ◽  
Direct Chill ◽  
Optical Metallography ◽  
Coarse Grain ◽  
Refined Grains ◽  
Microstructural Evaluation ◽  
Dc Casting ◽  
Scrap Aluminum

The melt conditioned direct chill (MC-DC) casting process has been used to produce billets and extruded planks of AA5754 alloy formulated from 100% recycled Taint Tabor scrap aluminum. The billets were homogenized and then extruded into flat planks. Optical metallography of the MC-DC cast billets showed equiaxed refined grains in comparison to conventional direct chill (DC) cast and direct chill grain refined (DC-GR) cast billets formulated from the same Taint Tabor scrap. Microstructural evaluation of the extruded planks showed extensive peripheral coarse grain (PCG) for the DC, DC-GR and MC-DC cast planks. The 2 mm and 1 mm MC-DC cast planks produced after cold rolling and heat treatment showed a fully recrystallized microstructure at 380 °C and 300 °C for 10 min respectively with an improvement in mechanical properties over DC-GR cast and similarly processed planks. The as-extruded MC-DC cast planks tensile tested in the transverse direction showed 34% elongation and 213 MPa ultimate tensile strength. These tensile results showed 5.8% higher elongation and 1.2% higher ultimate tensile strength compared with the DC-GR planks after applying high shear melt conditioning.

scholarly journals The Effect of Aging on Precipitates, Mechanical and Magnetic Properties of Fe-21Cr-15Ni-6Mn-Nb Low Magnetic Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 819
Author(s):  
Changsheng Li ◽  
Kun Li ◽  
Jingbo Dong ◽  
Jinyi Ren ◽  
Yanlei Song
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Magnetic Properties ◽  
Solution Heat Treatment ◽  
Aging Treatment ◽  
Relative Magnetic Permeability ◽  
Coarsening Behavior ◽  
The Matrix ◽  
Coherent Orientation

The effect of aging on the precipitates, mechanical and magnetic properties of Fe-21Cr-15Ni-6Mn-Nb low magnetic stainless steel were investigated. The steel was aged at 550–750 °C for 2 h after solution heat treatment at 1100 °C for 1 h. During the aging treatment, the (Nb, V)(C, N) particles gradually precipitated in the grain, which were coherent or semi-coherent with the matrix. When the aging temperature was beyond 650 °C, the coarsening rate of (Nb, V)(C, N) particles increase rapidly and the coherent orientation between (Nb, V)(C, N) particles and the matrix was lost gradually. Meanwhile, coarse M23C6 was distributed at the grain boundary with chain shape, which was non-coherent with the matrix. The coarsening behavior of (Nb, V)(C, N) precipitates in the grain was analyzed, and the size of the particles precipitated after aging treatment at 650°C for different time was calculated and studied. After aging treatment at 650 °C for 2 h, the yield strength and tensile strength of the stainless steel was 705.6 MPa and 1002.3 MPa, the elongation and the relative magnetic permeability was 37.8% and 1.0035, respectively.

Microstructure and Mechanical Properties of TiB2/ Al-Si Composites Fabricated by TIG Wire and Arc Additive Manufacturing

2019 ◽  
Vol 944 ◽  
pp. 64-72
Author(s):  
Qing Feng Yang ◽  
Cun Juan Xia ◽  
Ya Qi Deng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
Filler Wire ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Bulky sample was made by using TIG wire and arc additive manufacturing (WAAM) technology, in which Ф1.6 mm filler wire of in-situ TiB2/Al-Si composites was selected as deposition metal, following by T6 heat treatment. The microstructure and mechanical properties of the bulky sample before and after heat treatment were analyzed. Experimental results showed that the texture of the original samples parallel to the weld direction and perpendicular to the weld direction was similar consisting of columnar dendrites and equiaxed crystals. After T6 heat treatment, the hardness of the sample was increased to 115.85 HV from 62.83 HV, the yield strength of the sample was 273.33 MPa, the average tensile strength was 347.33 MPa, and the average elongation after fracture was 7.96%. Although pore defects existed in the fracture, yet the fracture of the sample was ductile fracture.

Modelling of the Metal/Mould Interactions in the DC Casting Process for Aluminium and Magnesium

2010 ◽  
Vol 654-656 ◽  
pp. 783-786 ◽  
Author(s):  
Arvin Prasad ◽  
Ian F. Bainbridge
Keyword(s):  
Heat Transfer ◽  
Casting Process ◽  
Direct Chill ◽  
Heat Extraction ◽  
Small Scale ◽  
Wall Region ◽  
Wall Heat Transfer ◽  
Mould Wall ◽  
Dc Casting ◽  
Basic Features

The process of direct chill (DC) casting of aluminium and magnesium alloys is regarded as a mature technology. The thrust of more recent work to understand and upgrade the technology has been centred on developing models of the process, the most advanced of which (e.g., Alsim and Calcasoft) have been used to examine what may be considered macro-features of the process (macro-segregation, hot cracking, etc.). These models, being macroscopic, rarely elaborate on the role of mould-wall heat transfer in the DC casting process. As part of the work on DC casting being conducted at CAST, for the investigation of small scale features of the process (e.g. heat extraction through the mould wall), a 2D finite Difference model of the process near the mould-wall region has been developed. The basic features of the model are described and initial results outlined.In particular, the effect of mould-wall heat transfer on the solid shell formed during the steady state regime of DC casting will be presented.

Application Research of a New Coupling Stirring on DC Casting Process for Large-Sized Aluminum Ingots

2015 ◽  
Vol 817 ◽  
pp. 48-54 ◽  
Author(s):  
Hai Jun Wang ◽  
Jun Xu ◽  
Zhi Feng Zhang ◽  
Bo Liang ◽  
Ming Wei Gao
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Casting Process ◽  
Direct Chill ◽  
Application Research ◽  
Center Position ◽  
Composition Segregation ◽  
Dc Casting ◽  
The Difference ◽  
7075 Alloy

A new coupling stirring technology was proposed and used to prepare direct chill (DC) ingots. Ingots of 7075 alloy were produced by a process of normal direct chill (NDC) casting and coupling-stirring direct chill (CDC) casting, respectively. The effect of the technology on the microstructures, composition segregation and mechanical properties of the ingots was investigated. The results showed that the temperature variation in the CDC casting process was more uniform than that in the NDC casting process. The grain of the CDC ingots was finer and more spherical than the grain of NDC ingots. The grain size at the edge, 1/2 radius, and center position in CDC ingot decrease by 28%, 22%, and 24% comparing with the grain size of the corresponding positions of NDC ingot, respectively. The billets with higher performance and lower macro-segregation were obtained in case of CDC. The flow stresses and the difference in different positions of DC ingots measured at Gleeble-1500D thermo-mechanical simulator decreased obviously when the coupling stirring technology is used in the casting process.

Microstructures of DC Cast Light Alloys under the Influence of Intensive Melt Shearing

2011 ◽  
Vol 690 ◽  
pp. 137-140 ◽  
Author(s):  
Yu Bo Zuo ◽  
Bo Jiang ◽  
Zhong Yun Fan
Keyword(s):  
Grain Refinement ◽  
Heterogeneous Nucleation ◽  
Solidification Process ◽  
Casting Process ◽  
Direct Chill ◽  
Light Alloy ◽  
High Quality ◽  
Light Alloys ◽  
Refined Microstructure ◽  
Dc Casting

A new direct chill (DC) casting process, melt conditioned DC (MC-DC) process has been developed for production of high quality ingots and billets of light alloys. In the MC-DC casting process, intensive melt shearing provided by a newly developed rotor-stator unit is used to control the solidification process during the DC casting with a conventional DC caster. Experimental results of DC casting of Al- and Mg-alloys with and without intensive melt shearing have demonstrated that the MC-DC casting process can produce light alloy billets with significantly refined microstructure and substantially reduced cast defects. The effect of intensive melt shearing on grain refinement has been mainly attributed to the enhanced heterogeneous nucleation on well dispersed oxides occurring naturally in the alloy melt.

Tensile Properties of Semi-Solid Die Cast AC4C Aluminum Alloy

2014 ◽  
Vol 680 ◽  
pp. 11-14
Author(s):  
Ke Ren Shi ◽  
Sirikul Wisutmethangoon ◽  
Jessada Wannasin ◽  
Thawatchai Plookphol
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Die Casting ◽  
Casting Process ◽  
Al Alloy ◽  
Die Cast ◽  
Die Casting Process ◽  
Semi Solid ◽  
Strength And Ductility

In this study, semi-solid Al-Mg-Si alloy (AC4C) was produced by using the Gas Induced Semi-Solid (GISS) die casting process. The tensile strength and ductility of the semi-solid die cast Al alloy (GISS-DC) after T6 heat treatment were investigated and compared with those of the conventional liquid die casting (CLDC). The microstructures of GISS-DC and CLDC observed by an optical microscopy were presented. The ultimate tensile strength (UTS) and yield strength (0.2% YS) of GISS-DC are compatible with those of the CLDC. However, the GISS-DC has better ductility than the CLDC, this may be due to the smaller and more globular primary α-Al phase and rounder shaped-Si particle microstructures presented in the GISS-DC. Common shrinkage pores and defects were also observed by SEM from the fracture surfaces of both alloys.

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