Effect of SiC particle size on the microstructure and properties of functionally graded Al-SiC composites produced via powder stacking method
Atefeh
Noohi
دانشجوی کارشناسی ارشد دانشکده تحصیلات تکمیلی دانشگاه آزاد اسلامی واحد تهران جنوب
author
Farshad
Akhlaghi
استاد دانشکده مهندسی متالورژی و مواد دانشگاه تهران
author
text
article
2015
per
In the present investigation powder stacking method was used for preparation of functionally graded Al-SiC composites. Commercially pure Al powder with the average size of 120 and SiC particels (with three average sizes of 50, 125 and 165 ) were used as the matrix and reinforcing phases respectively. Specified amounts of SiC and Al powder were mixed with each other via wet mixing using alcohol. Then the powder mixtures containing 0, 10, 15 and 20 vol.% of SiC particles were stacked on each other in a steel die, pressed at 750 Mpa and sintered in a tube furnace at 675 for 60 min. The cylindrical composite samples were sectioned along their height through their center line, grinded, polished and subjected to metallographic studies (via light microscopy) and Brinel hardness testing. Also their densities were quantified via Archemedos method. The results confirmed that by using fine SiC particles, Al-SiC composites with a smooth gradient of SiC concentration and porosity level along the height of the samples was achieved. The decreased size of SiC particles resulted in the decreased overall porosity of the samples which also depended on the concentration of SiC particles. The size of SiC particles affected both the hardness and distribution of particles in the samples.
Metallurgical Engineering
Iranian Metallurgical Engineers
1563-1745
18
v.
57
no.
2015
3
15
https://www.metalleng.ir/article_19386_37bdea4ab7eeee79571cdfc244395c5e.pdf
Effect of the Annealing Temperature, Cooling rate and Cold Rolling Reduction Rate on the Bake Hardening a Low Carbon Steel
ashkan
nouri
Assistant professor- department of materialas science and metallurgy-Arak university
author
حسین
حسن نژاد
استادیار گروه مهندسی مواد و متلورژی - دانشگاه اراک
author
جمال الدین
فرشته خصلت
مهندس/ شرکت مالیبل سایپا؛ دانش آموخته کارشناسی ارشد/دانشگاه آزاد کرج
author
text
article
2015
per
In this investigation, effect of annealing conditions as well as cold rolling reduction rate on the bake hardening property of low carbon steel was studied. This characterization is determined by measuring the yield stress increment between the values at 2% elongation and the higher yield strength due to strain aging after aging at 170C for 20 min. It was found to the annealing temperature has a significant effect in increasing the solute carbon content and enhancing bake hardening property. For the purposing of the role of cooling rate was applied two mode of cooling including slow and rapid cooling. It was observed that the cooling rate has not noticeably effect on the bake hardening value. However, in general, increasing cooling rate was caused increasing bake hardening property. This increasing could be due to prevention of carbide re-precipitation as well as making super saturation of carbon content in solid solution. Study of grain size showed that increasing this factor enhances bake hardenability.
Metallurgical Engineering
Iranian Metallurgical Engineers
1563-1745
18
v.
57
no.
2015
27
34
https://www.metalleng.ir/article_19388_b97080ee4ee767f5723f02d3fd3caa13.pdf
Effect of ingate velocity on bubble damage in Al-5Mg and 413 Casting Alloys
Hosein
Mokhlesian
MSc , Student
author
Mehdi
Divandari
Asso. Prof. in IUST
author
text
article
2015
per
Bubble damage is a casting defect related to the air entrainment as a result of unsuitable running system design and surface turbulence. In this work, effects of gate velocity on the formation of bubble damage in Al-5Mg and 413 casting alloys are investigated. Gate velocity was changed by increasing the sprue height and decreasing the ingate area. After casting radiography of plates and three points bend test, on samples taken from plates, was performed. Fractography of samples by SEM and quantitative analysis by EDS were also applied. Results show that size and quantity of entrapped air bubbles are increased as a result of increase in gate velocity. Area fraction and size of bubbles entrained in Al-5Mg alloy seems to be eight folds higher in comparison with 413 Al alloy. This observation confirms the hypothesis of the effect of oxide films thickness on the intensity of bubble damage in various Al alloy.
Metallurgical Engineering
Iranian Metallurgical Engineers
1563-1745
18
v.
57
no.
2015
16
26
https://www.metalleng.ir/article_19389_2181c99ff49d53363ca5442999c4ff8c.pdf
Effect of Heat Input on Microstructure and Wear Resistance of Stellite4 Cladded on15-5PH Stainless Steel using GTAW
رضا
خلیلی
فارغ التحصیل کارشناسی ارشد
author
Majid
Abbasi
عضو هیات علمی و مدیر مرکز رشد فناوری
دانشگاه صنعتی نوشیروانی بابل
author
text
article
2015
per
In this paper effect of heat input on the microstructure and wear resistance of cobalt base super alloy (stellite 4) cladded on precipitation hardened martensitic stainless steel 15-5PH were investigated. For this purpose, stellite 4 filler metal was clad on 15-5PH steel by gas tungsten arc welding process (GTAW). The different input heats were controlled as function of welding current, welding voltage and speed of cladding. The microstructure, hardness and wear resistance of clads were investigated by optical microscopy, scanning electron microscopy, Vickers micro-hardness and pin-on-disc wear tests. The results showed that the microstructure of the clad layer consists of dendritic Co-rich solid solution and lamellar eutectic carbides in inter-dendritic spaces. Decreasing the heat input creates a finer dendritic structure and finer eutectic carbides distribution. In addition decreasing the heat input reduces the dilution of iron in the clad layer. Therefore the hardness and wear resistance of clad increase by decreasing of heat input.
Metallurgical Engineering
Iranian Metallurgical Engineers
1563-1745
18
v.
57
no.
2015
35
43
https://www.metalleng.ir/article_19390_44eb698858ad533dbe7b076e68e14d51.pdf
Effect of iron addition on graded microstructure of Al-13.8 wt.% Mg2Si during centrifugal casting
Ahad
Samadi
دانشیار دانشگاه صنعتی سهند تبریز
author
Masomeh
Ghayebloo
کارشناس ارشد
author
Ava
Azadi
کارشناس
author
text
article
2015
per
The modification of microstructural grading of the cast hollow cylinders of eutectic composite Al-13.8 wt.% Mg2Si was studied via 0.5 wt.% Al-75Fe addition to the melt during centrifugal casting. The chemical composition, microstructure and hardness of different radial sections of the cast cylinders were studied using energy dispersive spectroscopy (EDX), optical microscope, scanning electron microscope, X-ray diffractometry and hardness testing, respectively. The results show that due to specific thermal regime, prevailed in centrifugal casting, the rod-shape fine eutectic microstructure in external periphery of the cast hollow cylinder changes to a coarse lamellar-shape eutectic microstructure in its internal periphery of cylinder. Also owing to segregation of FeAl3/Al8Fe2Si brittle particles with needle morphology towards the inner periphery of cylinder, thus their effective role in heterogeneous formation of Mg2Si and developing the α-Al in matrix phase, the inner periphery of the iron-contained cylinder showed the lower hardness in compared with the outer periphery of cylinder.
Metallurgical Engineering
Iranian Metallurgical Engineers
1563-1745
18
v.
57
no.
2015
44
53
https://www.metalleng.ir/article_19391_30d821986ff78e51fc5610a024909b40.pdf
Investigation structure and mechanical properties of commercial pure copper produced by Accumulative Roll Bonding (ARB) and Multi Axial Forging process (MAF)
امیرحسین
اسلامی
مربی دانشگاه آزاد اسلامی مشهد- گلبهار
author
سید هادی
حسینی
مربی دانشکده فنی شهید منتظری
author
افشین
کازرونی
استادیار گروه ساخت و تولید دانشگاه تربیت دبیر شهید رجائی
author
text
article
2015
per
Techniques of severe plastic deformation have been of continual interest in the production of novel metallic microstructures. Among these, accumulative roll bonding and multi axial forging have been extensively used in modern industry. Accumulative roll-bonding (ARB) and multi axial forging (MAF) process are severe plastic deformation process capable of developing grains below1m diameter and to improve mechanical properties. In this study, high strength and high rigidity copper were produce by ARB and MAF methods, using commercial pure copper to seven cycles. Mechanical and structure analyses were conducted on the produce specimen to evaluate their mechanical and structural properties in different ARB and MAF cycles. Hardness, yield stress, UTS and ductility properties of samples were determined by mechanical tests. The results show that hardness, yield strength and UTS of the axial forged and rolled samples are increased whereas the strain hardening decreased by increasing cycles. With increasing strain during ARB and MAF passes strength of these specimen increased but elongation decreased. According to the last analysis results, it can be said that multi axial forging in compare of ARB process can produce ultra-fine grained materials to improve the mechanical properties including tension and hardness
Metallurgical Engineering
Iranian Metallurgical Engineers
1563-1745
18
v.
57
no.
2015
54
62
https://www.metalleng.ir/article_19392_909add2728c2fc6d2d9fb5fa297de9e8.pdf