Effect of Mg, Sr, Ti and Aging Parameters on the Mechanical Behavior of 319 Alloys in the T5 and T6 Heat Treatment

2012 ◽  
Vol 482-484 ◽  
pp. 2275-2288
Author(s):  
Saleh Alkahtani
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aging Treatment ◽  
Magnesium Content ◽  
Air Cooling ◽  
Particle Spacing ◽  
Sr Modification ◽  
Heat Treated ◽  
Negative Effect ◽  
Mg Content

In this work, the effect of metallurgical parameters (i.e. alloy chemistry and aging parameters) on the mechanical properties of 319 alloys was investigated, with the aim of adjusting these parameters to produce castings of suitable mechanical properties. An attempt has been made to quantify the effects of alloying elements (Mg, Sr, and Ti) and aging parameters on the mechanical properties of heat-treated (T5 and T6) 319 alloys. Exploring the heat treatment differences between T5 and T6 for 319 alloys would help in selecting the metallurgical conditions required to achieve the optimum and maximum mechanical properties. Aging treatments were carried out for 319 alloys in the T5- and T6-condition at 150°C, 180°C, 200°C, 220°C and 250°C for 4, 8, 16, 24 and 48 h, followed by air cooling. Aging treatment at a lower temperature of 150°C produces fine and dense precipitates having a smaller inter-particle spacing, while at higher aging temperatures, such as 250°C, the precipitates are coarser in size, less dense, and more widely dispersed. For 319 alloys, crack initiate and propagate mainly through the debonding of Si particles from the Al matrix and through the cleavage of β-iron intermetallics. Fracture of intermetallic phases in the interdendritic regions is mostly brittle, with the formation of microcracks at the Si, Cu, Fe-base intermetallics and aluminium interfaces. Experimental correlations of the results obtained from the mechanical properties measurements are analyzed and correlations that relate the alloying additions and heat treatment to the ultimate tensile strength (UTS), yield strength (YS) and total percent elongation (%E) of such alloys are found. Different levels of magnesium content (%Mg), Sr-modification (Sr-ppm), aging parameters (temperature and time) were tested. The effect of alloy additions (Mg, Sr and Ti) and aging heat treatment parameters (Temperature and Time) on the mechanical properties and alloy performance of cast and heat treated 319 alloys are investigated. It was found that the strength of 319 alloys increases with the magnesium content and decreases with the Sr-modification (Sr-ppm) and aging parameters (temperature and time). Increasing the Mg content in primary 319 alloys up to 0.45% enhances the alloy response to heat treatment in the T5 and T6 Tempers, more particularly, the T6 one. Sr-Modification of high Mg content 319 alloy in amounts of ~360 ppm leads to a noticeable decline in alloy strength due to porosity formation which counteracts the beneficial effect of the modification. Sr-modification has a negative effect on the % elongation results of Mg-content 319 alloys due to the Mg-Sr interaction in the aged-T6 conditions. However, grain refining of the Mg and Sr content 319 alloys produce sounder castings with finer grain sizes

Mechanical Behavior of Friction Stir Welded AA-6061 Thick Plates in Different Heat Treatment Conditions

2021 ◽  
Vol 875 ◽  
pp. 203-210
Author(s):  
Talha Ahmed ◽  
Wali Muhammad ◽  
Zaheer Mushtaq ◽  
Mustasim Billah Bhatty ◽  
Hamid Zaigham
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aging Treatment ◽  
Travel Speed ◽  
Butt Joint ◽  
Tensile Fracture ◽  
Friction Stir ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Joint Form

In this study, mechanical properties of friction stir welded Aluminum Alloy (AA) 6061 in three different heat treatment conditions i.e. Annealed (O), Artificially aged (T6) and Post Weld Heat Treated (PWHT) were compared. Plates were welded in a butt joint form. Parameters were optimized and joints were fabricated using tool rotational speed and travel speed of 500 rpm and 350 mm/min respectively. Two sets of plates were welded in O condition and out of which one was, later, subjected to post weld artificial aging treatment. Third set was welded in T6 condition. The welds were characterized by macro and microstructure analysis, microhardness measurement and mechanical testing. SEM fractography of the tensile fracture surfaces was also performed. Comparatively better mechanical properties were achieved in the plate with PWHT condition.

The Effect of Heat Treatment on Fatigue and Mechanical Properties of 6061 Aluminium Alloy

2014 ◽  
Vol 699 ◽  
pp. 227-232
Author(s):  
Nurulhilmi Zaiedah Nasir ◽  
Mohd Ahadlin Mohd Daud ◽  
Mohd Zulkefli Selamat ◽  
Ahmad Rivai ◽  
Sivakumar Dhar Malingam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Strength ◽  
Aluminium Alloy ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Hardness Tester ◽  
Quenching Media ◽  
Heat Treated ◽  
6061 Aluminium Alloy

This paper investigated the effect of heat treatment on mechanical properties and microstructure of 6061 aluminium alloy. The aluminium alloys were examined in the heat treated conditions, using different quenching media, water and oil. The alloy was solution heat treated at temperature of 529oC for one, three and five hour respectively. Aging treatment was carried out at temperature of 160oC which is assumed to be the best temperature for ageing process. Hardness measurement was carried out using a Brinell Hardness Tester Machine. The results shows hardness and impact strength are inversely proportional to each other, as the hardness of 6061 aluminium alloy decreases and impact strength increases.

The Microstructure and Compression Behavior of Multi-Step Forging Ti-45Al-8Nb Alloy after Annealing at 1100 °C

2013 ◽  
Vol 747-748 ◽  
pp. 111-114
Author(s):  
Lin Song ◽  
Xiang Jun Xu ◽  
Jun Pin Lin ◽  
Lai Qi Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Annealing Treatment ◽  
Air Cooling ◽  
Test Machine ◽  
Compressive Properties ◽  
Compression Behavior ◽  
Microstructure Change ◽  
Heat Treated ◽  
Before And After

Effects of annealing treatment on microstructure and the compressive properties of hot-worked Ti-45Al-8Nb-(W, B, Y) alloy were investigated. Microstructure of the extrusion plus multi-step forging pancake before and after heat treatment was analyzed by SEM and TEM, respectively. The annealing was conducted by holding samples at 1100°C for 2hrs, and followed by air cooling and furnace cooling. The mechanical properties were measured by Instron test machine. The microstructure evolution during compressive deformation was analyzed by TEM. The results showed that after the annealing the microstructure change could not be observed under SEM but can be observed under TEM. Many dislocation clusters were removed by heat treatment. The heat treated samples had similar compression behaviors with the pancake. TEM investigation showed that the numerous twin intersections occured in γ matrix during compression. The twin spaces tended to decrease as the deformation and the intersection increasing.

Microstructural Evolution and Mechanical Properties of Modified 9%Cr-1%Mo Steel upon Isothermal Heat-Treatment

2005 ◽  
Vol 475-479 ◽  
pp. 81-84
Author(s):  
Sung Kang Hur ◽  
Kee Sam Shin ◽  
Jung Hoon Yoo ◽  
Ja Min Koo ◽  
Soo Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
Microstructural Evolution ◽  
Heat Treating ◽  
Air Cooling ◽  
Isothermal Heat Treatment ◽  
Martensitic Structure ◽  
Heat Treated ◽  
Evolution Of Microstructure

The evolution of microstructure and its effects on the mechanical properties of modified 9%Cr-1%Mo steel during heat-treating at 1050°C for 15 min and then isothermal heat treatment at 380~760°C with subsequent air-cooling have been investigated. For the microstructural and mechanical property analyses, OM, SEM, EDS, XRD, hardness and impact tests were used. In accordance with the severity of the heat-treatment, the microstructure evolved from the untransformed martensite to the partially transformed dual phases of martensite and ferrite, and then fully transformed to ferrite. Impact values at ambient temperature for specimens isothermally heat-treated at 320 - 380°C, predominantly at about 350°C were lower than others’ with similar martensitic structure. The partially transformed specimens with dual phases of martensite and ferrite also showed lower impact values than samples with untransformed with martensitic, and transformed with ferritic structures.

Experimental Correlation between Metallurgical Parameters, Hardness and Machinability of 319 Al-Si-Cu-Mg Alloys

2011 ◽  
Vol 339 ◽  
pp. 462-476
Author(s):  
Mahmoud M. Tash ◽  
Saleh Alkahtani
Keyword(s):  
Aging Time ◽  
High Speed ◽  
Statistical Design ◽  
Magnesium Content ◽  
Air Cooling ◽  
Statistical Design Of Experiments ◽  
Alloying Additions ◽  
Sr Modification ◽  
Heat Treated ◽  
Fe Intermetallics

An attempt has been made to quantify the effects of alloying elements and aging parameters on the hardness and machinability of heat-treated 319 alloys containing α-Fe or β-Fe intermetallics An understanding of these parameters would help in selecting the metallurgical conditions required to achieve the optimum and maximum productivity at high speed machining. Hardness measurements were carried out on specimens prepared from 319 alloys in the as-cast and heat-treated conditions, using different combinations of grain refining, Sr-modification, and alloying additions. Aging treatments were carried out at 155°C, 180°C, 200°C, and 220°C for 4 h, followed by air cooling, as well as at 180°C and 220°C for 2, 4, 6, and 8 h to determine conditions under which specific hardness levels could be obtained. Statistical design of experiments is a satisfactory method for quantifying the effect of various parameters. Experimental correlations of the results obtained from the hardness measurements are analyzed and correlations that relate the alloying additions and heat treatment to the hardness of such alloys are found. Two levels of magnesium content (%Mg), volume fractions of the Fe-intermetallics (%V.F), Sr-modification (Sr-ppm), aging parameters (temperature and time) were tested: 0.1% and 0.28% for Mg, 2% and 5% for Fe-intermetallics (%V.F), 0-ppm and 200-ppm for Sr-modification, 180°C and 220°C for aging temperature and 2h. and 8h. for aging time. Experimental correlations between the metallurgical parameters and the machinability values obtained were analyzed. For this, two levels of Mg (0.1 and 0.28 wt%), Fe-intermetallics (2% and 5%), and two aging temperatures (180°C and 220°C) and aging time of 2h were selected.

Effect of Strontium and T6 Heat Treatment on Structure and Performance of Al-11.6Si-0.5Mg Alloy

2013 ◽  
Vol 749 ◽  
pp. 1-6
Author(s):  
Ji Xing Lin ◽  
Jun Ping Zhang ◽  
Li Yuan Niu ◽  
Da Ren Sun ◽  
Zi Mu Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Eutectic Structure ◽  
Air Cooling ◽  
Water Cooling ◽  
T6 Heat Treatment ◽  
Sr Modification ◽  
Economic Process ◽  
And Performance ◽  
Microstructure And Performance

In this study, Strontium (Sr) was added as modifier during the casting of Al-11.6Si-0.5Mg alloy, and the effect of T6 heat treatment on microstructure and performance of alloy was also investigated. The results showed that the 0.3% Al-8%Sr master alloy can refine effectively the α-Al dendrite and eutectic structure; the best economic process of T6 heat treatment is solution at 535°C for 6 hrs., and water cooling at 50~60°C,aging at 160°C for 6 hrs , then air cooling. After Sr modification and T6 heat treatment, the mechanical properties of alloy are improved remarkably, i.e., the tensile strength increased to 348MPa from 183MPa before modification and the elongation raises from 3.0% to 6.5%. So this alloy is applied to the strain clamp products in electric power fitting industry.

Crystallographic Differences of Metastable NI2MO in a NI-MO-AL Superalloy

1980 ◽  
Vol 38 ◽  
pp. 158-159
Author(s):  
Michael M. Kersker ◽  
E. A. Aigeltinger ◽  
J. J. IIren
Keyword(s):  
Mechanical Properties ◽  
Air Cooling ◽  
Solution Treated ◽  
Heat Treated ◽  
Metastable Compounds ◽  
Rapidly Solidified

Ni-rich alloys based on approximate ternary composition Ni-8Mo-15A1 (at%) are presently under investigation in an attempt to study the contribution, if any, of the profusion of Mo-rich NixMo metastable compounds that these alloys contain to their excellent mechanical properties. One of the alloys containing metastable NixMo precipitates is RSR 197 of composition Ni-8.96Mo-15.06A1-1.98Ta-.015Yt. The alloy was prepared at Pratt and Whitney Government Products Division, West Palm Beach, Florida, from rapidly solidified powder. The powder was canned under inert conditions and extruded as rod at 1315°C. The as-extruded rod, after air cooling, was solution treated at 1315°C for two hours, air cooled, and heat treated for one hour at 815°C, followed again by air cooling.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

The Effect of Aging Heat Treatment on the Microstructure and Mechanical Properties of 10Cr20Ni25Mo1.5NbN Austenitic Steel

2016 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Zhiyuan Liang ◽  
Wanhua Sha ◽  
Qinxin Zhao ◽  
Chongbin Wang ◽  
Jianyong Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Austenitic Steel ◽  
Treatment Time ◽  
Aging Treatment ◽  
Secondary Phases ◽  
Aging Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
The Impact

AbstractThe effect of aging heat treatment on the microstructure and mechanical properties of 10Cr20Ni25Mo1.5NbN austenitic steel was investigated in this article. The microstructure was characterized by scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy. Results show that the microstructure of 10Cr20Ni25Mo1.5NbN austenitic is composed of austenite. This steel was strengthened by precipitates of secondary phases that were mainly M23C6 carbides and NbCrN nitrides. As aging treatment time increased, the tensile strength first rose (0–3,000 h) and then fell (3,000–5,000 h) due to the decrease of high density of dislocations. The impact absorbed energy decreased sharply, causing the sulfides to precipitate at the grain boundary. Therefore, the content of sulfur should be strictly controlled in the steelmaking process.

Application of Tailored Heat Treated Blanks under Quasi Series Conditions

2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Local Heat ◽  
Strength Distribution ◽  
Process Window ◽  
Short Term ◽  
Forming Process ◽  
Heat Treated ◽  
Set Up ◽  
The Impact

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.

Sign in / Sign up

Export Citation Format

Share Document