Effect of Heat Treatment Hardness of Al-Cu-Mg-Li-Zr, Al-Mg-Si and and Al-Mg-Zn Alloys-Experimental Correlation Using Factorial DOE and ANOVA Methods

2014 ◽  
Vol 881-883 ◽  
pp. 1317-1329 ◽  
Author(s):  
Mahmoud M. Tash ◽  
Saleh Alkahtani

The present study was conducted to investigate the effect of heat treatment on the aging and mechanical behavior of Al-Cu-Mg-Li-Zr , Al-Mg-Si and and Al-Mg-Zn alloys (8090 , 6082 and 7075). The effect of cold work after solution treatment, aging parameters (time and temperature) on the microstructure and mechanical properties were studied. Attempts are made to determine the combined effect of cold work and aging treatment on the hardness, UTS and microstructure for these alloys. By study the impact of different heat treatments for Al-Mg-Si alloys (6082), Al-Cu-Mg-Li-Zr (8090) and Al-Mg-Zn (7075) aluminum alloys on the hardness and mechanical properties, it is possible to determine conditions necessary to achieve better mechanical properties and the maximum levels of hardness and values corresponding to those considered suitable for commercial applications of these alloys.Design of Experiment (DOE) method in Minitab is used to measure the impact of various factors and how they relate. Correlation between the hardness and different metallurgical factors for these alloys at both quantitative and qualitative are investigated and analysed. A statistical design of experiments (DOE) approach using fractional factorial design was applied to determine the influence of controlling variables of cold work and heat treatment parameters and any interactions between them on the hardness of the above alloys. A mathematical model is developed to relate the alloy hardness with the different metallurgical parameters to acquire an understanding of the effects of these variables and their interactions on the hardness of wrought Al-alloys. It is noticed that cold work, following solution treatment, accelerates the precipitation rate leading to a rise in strength

2016 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Zhiyuan Liang ◽  
Wanhua Sha ◽  
Qinxin Zhao ◽  
Chongbin Wang ◽  
Jianyong Wang ◽  
...  

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.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4223 ◽  
Author(s):  
Xi Zhao ◽  
Shuchang Li ◽  
Fafa Yan ◽  
Zhimin Zhang ◽  
Yaojin Wu

Microstructure evolution and mechanical properties of AZ80 Mg alloy during annular channel angular extrusion (350 °C) and heat treatment with varying parameters were investigated, respectively. The results showed that dynamic recrystallization of Mg grains was developed and the dendritic eutectic β-Mg17Al12 phases formed during the solidification were broken into small β-phase particles after hot extrusion. Moreover, a weak texture with two dominant peaks formed owing to the significant grain refinement and the enhanced activation of pyramidal <c + a> slip at relative high temperature. The tension tests showed that both the yield strength and ultimate tensile strength of the extruded alloy were dramatically improved owing to the joint strengthening effect of fine grain and β-phase particles as compared with the homogenized sample. The solution treatment achieved the good plasticity of the alloy resulting from the dissolution of β-phases and the development of more equiaxed grains, while the direct-aging process led to poor alloy elongation as a result of residual eutectic β-phases. After solution and aging treatment, simultaneous bonding strength and plasticity of the alloy were achieved, as a consequence of dissolution of coarse eutectic β-phases and heterogeneous precipitation of a large quantity of newly formed β-phases with both the morphologies of continuous and discontinuous precipitates.


2007 ◽  
Vol 567-568 ◽  
pp. 361-364 ◽  
Author(s):  
Suk Bong Kang ◽  
Jae Hyung Cho ◽  
Hyoung Wook Kim ◽  
Y.M Jin

The sheet of ZK60 alloy with a thickness of 1mm was prepared from a casting ingot followed by homogenization and warm-rolling. Variations in microstructure and mechanical properties of ZK60 alloy sheets were investigated during T6 treatment. Especially artificial aging after solution heat treatment affected both precipitates distribution and mechanical properties with aging treatment. Variations of mechanical properties were related to precipitates, i.e. rod-shaped ( 1 β ′ ) or disc shaped ( 2 β ′ ) particles. Around the peak of hardness values, regularly distributed rod-shaped ( 1 β ′ ) precipitates were found. The rod-shaped ( 1 β ′ ) precipitates were oriented with a growth direction of [0001]. When over-aged, rod-shaped ( 1 β ′ ) precipitates were expected to decrease and the density of disc-shaped ( 2 β ′ ) precipitates to change. The rod-shaped ( 1 β ′ ) precipitates mainly consist of {Mg, Zn}, while disc-shaped ( 2 β ′ ) precipitates, {Mg, Zn, Zr} or {Mg, Zn}. In this study the optimum T6 treatment was determined as solution treatment at 430 °C for 6 hours and subsequently aging treatment at 175 °C for 18 hours. At this T6 condition the tensile strength, yield strength and elongation are 321MPa, 280MPa and 16%, respectively.


2021 ◽  
Vol 1042 ◽  
pp. 111-115
Author(s):  
Dwi Rahmalina ◽  
Hendri Sukma ◽  
Abdul Rokhim ◽  
Amin Suhadi

Metal matrix composite has been developed to improve mechanical properties for the automotive component application. One crucial factor in achieving excellent mechanical properties is improving the properties of the aluminum matrix of composite by the heat treatment process. The mechanical properties of Al-Mg-Si matrix composites alloyed with Zn and reinforced with 5% SiC and 5%Gr particle were examined after the heat treatment process. The aluminum matrix is melted inside the crucible furnace at 850 °C and is added with SiC/Gr particle, followed by stirring at 7500 rpm to optimize the mixing of the composite. Then, the composite is poured into the preheated mold at 300 °C and then squeezed with 30 MPa of pressure. The heat treatment process consists of three steps; solution treatment, quenching, and artificial aging. The aging process is conducted with variation of temperature (140 °C, 180 °C and 200 °C) and holding time (2, 4, and 6 hours). The test results show that the mechanical properties of aluminum matrix composite tend to increase after the heat treatment process. The optimum mechanical properties are achieved at the aging temperature of 200 °C for 6 hours, with the hardness value of 60.3 HRA and the impact value of 0.112 Joule/mm2.


2011 ◽  
Vol 467-469 ◽  
pp. 257-262
Author(s):  
Guo Fa Mi ◽  
Jin Zhi Zhang ◽  
Hai Yan Wang

Alloys were produced by casting of Cu-Al-Fe-Be and Cu-Al-Fe-Ni aluminum bronzes and aged. The microstructures and mechanical properties were evaluated. The results indicated that solution and aging treatment can significantly improve the plasticity of Cu-Al-Fe-Be and Cu-Al-Fe-Ni, while the strength and hardness remained in the quenched level. Extending the aging time can effectively enhance the mechanical properties of alloys, and the longer the aging time, the higher the electric resistance of alloys. According to the results, the mechanical properties of the Cu-Al-Fe-Be alloy can be improved remarkably by solution treatment for 120 min at 950°C, followed by aging treatment for 120 min at 350°C, and quenched. While the most suitable heat treatment for the Cu-Al-Fe-Ni alloy was solution treatment 120 min at 950°C, followed by aging for 120 min at 450°C, and quenched. The experimental result also suggested that the Cu-Al-Fe-Be alloy possessed higher hardness and tensile strength compared to the Cu-Al-Fe-Ni alloy.


2011 ◽  
Vol 194-196 ◽  
pp. 1319-1325
Author(s):  
Zheng Tian ◽  
Zhan Yi Cao ◽  
Jian Meng

The effect of yttrium addition and heat treatment on the mechanical properties and microstructure of AM60 magnesium alloy have been investigated using X-ray phase analysis, microstructure investigation, tensile test, hardness measurement and fracture surfaces analysis. The results showed that the mechanical properties of the alloys were obviously improved with the addition of yttrium no more than 1.0%. The reinforcement of the alloys resulted from the appearance of Al2Y phase. After solid-solution treatment (T4), the Mg17Al12 phase almost dissolved in Mg matrix, but the rare earth compounds Al2Y phase was rather stable. The ultimate tensile strength σb was improved, but the yield strength σ0.2 and elongation δ were only slightly changed. After solid-solution + aging treatment (T6), the Mg17Al12 phase precipitated again and their morphology was changed. The yield strength σ0.2 was improved.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 268
Author(s):  
Ji-Hoon Jang ◽  
Dong-Geun Lee

The cytotoxic tissue reactions of alloying elements (Al, V) of Ti-6Al-4V have been reported, whereas the Ti-39Nb-6Zr (TNZ40) alloy developed by adding β-phase stabilizing elements is known to have no cytotoxicity and exhibits excellent biocompatibility. In addition, there is a slight modulus difference between the TNZ40 alloy and human bones as the elastic modulus of the TNZ40 alloy is very low. This can inhibit detrimental effects such as osteoblast loss due to a stress-shielding effect. In this study, various Si contents were added and heat treatment under various conditions was performed to control the microstructure and mechanical properties of the TNZ40 alloy. In the β-type titanium alloy, the ω phase is commonly observed by quenching from the solution-treatment or aging-treatment temperature. These ω precipitates can typically increase the elastic modulus, hardness, and embrittlement of the β-type titanium alloy, which are important to control this phase. The correlation between Si content and precipitation and the effects of solution treatment and aging condition on the mechanical properties such as tensile strength, and hardness, were analyzed.


2017 ◽  
Vol 898 ◽  
pp. 380-386
Author(s):  
Wei Yuan ◽  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Guo Liang Xie

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.


2018 ◽  
Vol 941 ◽  
pp. 668-673 ◽  
Author(s):  
Yi Fan Feng ◽  
Ren Bo Song ◽  
Zhong Zheng Pei ◽  
Lun Li

In this paper, the microstructural evolution and mechanical properties of the as-cast Fe-25Mn-7Al-1.3C austenitic steel after different heat treatment were investigated. After solution treatment and subsequent aging treatment, the κ-carbides with perovskite structure were found to precipitate coherently within the austenite matrix, which improved the initial hardness and mechanical strength. The experimental steel exhibited an optimal comprehensive performance after being solution treated at 1050 °C for 1 h and then aged at 550 oC for 2 h. The tensile strength was 751 MPa, the yield strength was 581 MPa, the elongation was 48%, the hardness was 252 HB, and the Charpy V-notch impact toughness was 168 J, respectively. The impact wear test was carried out on MLD-10 abrasive wear testing machine, and the worn out surfaces under different heat treatment were characterized by scanning electron microscopy (SEM). The results indicated that the abrasion resistance of the steel under the additional aging treatment was better than that of the as-solutionized steel. The optimal abrasion resistance was obtained after being soluted at 1050 °C for 1 h and then aged at 550 oC for 2 h. However, with the aging time increasing, the coarse κ-carbides precipitating around the grain boundaries would deteriorate toughness, which lead to increase of the abrasive wear volume loss. Besides, obvious micro-cracking and relatively larger peeling pit were observed.


2012 ◽  
Vol 562-564 ◽  
pp. 242-245 ◽  
Author(s):  
Ming Tan ◽  
Zhao Ming Liu ◽  
Gao Feng Quan

The effects of heat treatment on the microstructure, tensile property and fracture behavior of as-extruded AZ91 magnesium alloy were studied by OM and SEM. The results show that the grain of as-cast AZ91 alloy is refined by extruding and dynamic recrystallization, and the mechanical properties increase obviously. The ductility is significantly enhanced after solution treatment of the as-extruded AZ91 alloy, tensile strength is almost the same before and hardness is significantly reduced after solution treatment and artificial aging treatment. The tensile strength reduced and the ductility is significantly enhanced of as-extruded AZ91 magnesium alloy after annealing processes. The fracture surface of as-extruded AZ91 magnesium alloy has the mixture of ductile and brittle characteristic. But after T6 or annealing treatment, its dimple number increases evidently.


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