Effects of recrystallization temperature on the mechanical properties of CuZn30 alloy

Author(s):  
Ali Muhammed ◽  
Abdulrahman Abed ◽  
Mustafa Adnan Mustafa
2021 ◽  
Vol 63 (1) ◽  
pp. 73-78
Author(s):  
Pulkin Gupta ◽  
Sudha Kumari ◽  
Abhishek Gupta ◽  
Ankit Kumar Sinha ◽  
Prashant Jindal

Abstract Fused deposition modelling (FDM) is a layer-by-layer manufacturing process type of 3D-printing (3DP). Significant variation in the mechanical properties of 3D printed specimens is observed because of varied process parameters and interfacial bonding between consecutive layers. This study investigates the influence of heat treatment on the mechanical strength of FDM 3D printed Polylactic acid (PLA) parts with constant 3DP parameters and ambient conditions. To meet the objectives, 7 sets, each containing 5 dog-bone shaped samples, were fabricated from commercially available PLA filament. Each set was subjected to heat treatment at a particular temperature for 1 h and cooled in the furnace itself, while one set was left un-treated. The temperature for heat treatment (Th) varied from 30 °C to 130 °C with increments of 10 °C. The heat-treated samples were characterized under tensile loading of 400 N and mechanical properties like Young’s modulus (E), Strain % ( ε ) and Stiffness (k) were evaluated. On comparing the mechanical properties of heat-treated samples to un-treated samples, significant improvements were observed. Heat treatment also altered the geometries of the samples. Mechanical properties improved by 4.88 % to 10.26 % with the maximum being at Th of 110 °C and below recrystallization temperature (Tr) of 65 °C. Deformations also decreased significantly at higher temperatures above 100 °C, by a maximum of 36.06 %. The dimensions of samples showed a maximum decrease of 1.08 % in Tr range and a maximum decrease of 0.31 % in weight at the same temperature. This study aims to benefit the society by establishing suitable Th to recover the lost strength in PLA based FDM 3D printed parts.


2010 ◽  
Vol 638-642 ◽  
pp. 3479-3484 ◽  
Author(s):  
Roberta O. Rocha ◽  
Tulio M.F. Melo ◽  
Dagoberto Brandao Santos

The influence of continuous annealing variables on the microstructure and mechanical properties of a C-Mn Dual Phase (DP) steel was studied. The annealing cycles were simulated using a Gleeble machine. Some specimens were quenched at different stages of the annealing cycle in order to evaluate the microstructural evolution during the annealing process. Tensile tests and microstrutural analysis were carried out. The results showed that high heating rates increased the final recrystallization temperature and as a consequence the microstructure obtained was refined. Austenite grain nucleation and growth were also influenced by the heating rates. Soaking temperature was the most influent variable on the mechanical properties, i. e., the yield strength increased and the tensile strength decreased with an increase in the soaking temperature. Microstructural analysis showed that not only martensite, but also bainite and martensite-retained autenite constituent (MA) were formed. Undissolved carbides were also detected by transmission electron microscopy.


2018 ◽  
Vol 153 ◽  
pp. 01001
Author(s):  
Maya Putri Agustianingrum ◽  
Nuzulian Akbar Arandana ◽  
Risly Wijanarko ◽  
Bondan Tiara Sofyan

In order to produce structural products, Al-Zn-Mg alloys undergo various forming processes. Problems that are usually found in the forming process include peripheral coarse grain (PCG) and hot tearing which decrease mechanical properties and corrosion resistance of the alloys. Addition of microalloying element such as chromium (Cr) is an alternative to overcome these problems. The presence of Cr in Al-Zn-Mg alloys supresses the grain growth by preventing excess recrystallization. In this research 0.9 wt. % Cr was added to Al-4.5Zn-1.5Mg alloy and the deformation behaviour as well as subsequent recrystallization was observed. The alloy was fabricated by squeeze casting followed by homogenization at 400 °C for 4 h. The samples were cold rolled for 5, 10, and 20 %. The 20 % deformed samples were then annealed at 300, 400, and 500 °C for 2 h. Material characterization consisted of microstructure analysis using optical microscope and Scanning Electron Microscope (SEM) – Energy Dispersive Spectroscopy (EDS), hardness testing using Micro Vicker methods. The results showed that the deformed grain ratio was 1.6, 2.84, and 2.99 in the 5, 10, and 20 % deformed samples, respectively. The elongated dendrites were effective to increase the hardness of the alloy. Recrystallization was not detected during annealing at 300 and 400 °C, but was observed at 500 °C. Whereas, for the samples without Cr addition, recrystallization occurred at 400 °C. It means that the addition of Cr increased the recrystallization temperature of the alloy. It occured because (Al, Zn)7Cr dispersoids with size less than 1 μm impeded the dislocation motion during annealing, so that recrystallization was retarded. On the other hand (Al, Zn)7Cr dispersoids with size more than 1 μm promoted the formation of new grains around them by Particle Stimulated Nucleation (PSN) mechanism. In this case, the fine (Al, Zn)7Cr dominated so that recrystallization was slower.


2010 ◽  
Vol 129-131 ◽  
pp. 1022-1028
Author(s):  
Daavood Mirahmadi Khaki ◽  
A. Akbarzadeh ◽  
Amir Abedi

Thermo mechanical processing and controlled rolling of microalloyed steel sheets are affected by several factors. In this investigation, finishing temperature of rolling which is considered as the most effective parameters on the final mechanical properties of hot rolled products has been studied. For this purpose, three different finishing temperatures of 950, 900 and 850 °C below the non-recrystallization temperature and one temperature of 800 °C in the intercritical range were chosen. It is observed that decreasing the finishing temperature causes increase of strength and decrease of total elongation. This is accompanied by more grain refinement of microstructure and the morphology was changed from polygonal ferrite to acicular one. Findings of this research provide suitable connection among finishing temperature, microstructural features, and mechanical properties of hot rolled Nb-microalloyed steel sheets.


2008 ◽  
Vol 584-586 ◽  
pp. 661-666 ◽  
Author(s):  
Enrico Bruder ◽  
Tilman Bohn ◽  
Clemens Müller

Linear flow splitting is a new cold forming process for the production of branched sheet metal structures. It induces severe plastic strain in the processing zone which results in the formation of an UFG microstructure and an increase in hardness and strength in the flanges. Inbuilt deformation gradients in the processing zone lead to steep gradients in the microstructure and mechanical properties. In the present paper the gradients in the UFG microstructure and the mechanical properties of a HSLA steel (ZStE 500) processed by linear flow splitting are presented, as well as a calculation of local strength from hardness measurements on the basis of the Ludwikequation. In order to investigate the thermal stability of the UFG microstructure heat treatments below the recrystallization temperature were chosen. The coarsening process and the development of the low angle to high angle grain boundary ratio in the gradient UFG microstructure were monitored by EBSD measurements. It is shown that heat treatment can lead to a grain refinement due to a strong fragmentation of elongated grains while only little coarsening in the transverse direction occurs. A smoothing of the gradients in the UFG microstructure as well as in the mechanical properties is observed.


1963 ◽  
Vol 85 (2) ◽  
pp. 279-285 ◽  
Author(s):  
M. E. Sikorski

The coefficients of adhesion determined by a modification of the twist-compression bonding method are compared with the following properties of metals: crystal structure, hardness, surface energy, elastic modulus, work-hardening properties, recrystallization temperature, purity, and atomic volume. Conclusions are reached regarding the desirable characteristics of metals, or combinations of metals, for antifriction applications.


2019 ◽  
Vol 285 ◽  
pp. 210-218
Author(s):  
Ju Fu Jiang ◽  
Ying Zhe Liu ◽  
Guan Fei Xiao ◽  
Ying Wang

Semisolid slurries of four wrought alloys were fabricated via partial melting of commerical wrought aluminum alloy. Thixoforming experiments of four typical parts were performed. The results showed that a large amount of equiaxed grains before soaking in semisolid state were created due to recrystallization occurred in the continuous heating from room temperature to a given temperature above recrystallization temperature. It provides a desirable microstructure to form spheroidal grains during the next soaking process in semisolid state. The microstructure of the 2A12,7A04 and 7075 semisolid slurry consisted of fine and spheroidal grains. The elongation of the thixoformed parts were higher those of the hot-rolled plate. The UTS of the thixoformed parts were close or ever higher than those of the hot-rolled plate. Although the grain size and roundness of the 5A06 semisolid slurry are not very desirable, the mechanical properties of the thixoformed part are close or ever than those of the hot-rolled plate. The high mechanical properties of the thixoformed parts further confirmed the feasibility of short-process thixoforming route


2020 ◽  
Vol 835 ◽  
pp. 324-334
Author(s):  
Maha El-Meligy ◽  
Taher El-Bitar

The present article presents cumulative works, which were carried out in the field of micro-alloying steel processing at Central Metallurgical R&D Institute (CMRDI) and/or full scale trials in collaboration with the Egyptian steel industry.It was agreed upon defining three main generations of processing micro-alloying steel. The 1stgeneration starts officially on 1975 and continues up to 1995, where it deals with using Ti and V as micro-alloying elements for steel long products. On the year 1985, Central Metallurgical R&D Institute (CMRDI) succeeded to implement of HSLA V-micro-alloyed rebar steel grades at Delta steel mills instead of conventional rebar grades.The 2nd generation was starting on late 1995 and continued to 2005. It was dealing mainly with low carbon content steel (0.04-0.08 %) for flat products (plate and sheet). The most successfully used micro-alloying element was Nb. Beside its precipitate forming effect, Nb is working as substitution solid solution strengthener. Moreover, it raises the recrystallization temperature (Tr). Mainly, micro-alloyed flat steels were developed to fulfill the requirements of the American Petroleum Institute (API) specifications 5L- Product Specification Levels (PSL1) and (PSL2) for manufacturing oil and natural gas pipelines. Meanwhile, a newly born Compact Slab Processing (CSP)-hot strip direct rolling technology was created. On years 2002, the metal forming department in CMRDI succeeded to implement controlled rolling of hot strip Nb-steel sheet at the Compact Slab Process (CSP) Machine in Alexandria National Iron and Steel (ANSDK) Company. Controlled hot rolling schedules were used and followed by early and late cooling at the run out table (ROT). Both contracts were fruitfully succeeded to introduce the API X52 grade at ANSDK Company, followed by X60, and X70 steel grades at Ezz Flat Steel (EFS) Company. The essential mechanical properties of the processed API steel sheets were matched with the API 5L-PSL2 specifications.The 3rd generation was initially developed after 2005 and continued up to day. It deals with micro-alloying with special functional elements like Boron (B). Boron was favored as a micro-alloying element for bilateral effects. Boron carbide (B4C) precipitates are the hardest after diamond, which would be reflected on raising the mechanical properties of the steel. Moreover, Boron was favorably used because it delays the temper embrittlement phenomena. On year 2014, the National for Military Industrialization authority requested from CMRDI to collaborate with Military Factory 100 to develop a technology package for processing armor steel plates. Trials were started with a 3rd generation B-micro-alloyed steel alloy. Many other alloying elements were used beside Boron to develop extra high strength 6.0 mm thickness plates. Finish hot rolled plates were then subjected to a subsequent water quenching from 900 °C and followed by tempering at 250 °C for 20 min. Representation 50X50 cm2 steel plates were successfully passed after 3 bullets in front and 3 bullets rear shooting.


2005 ◽  
Vol 495-497 ◽  
pp. 537-542 ◽  
Author(s):  
S.I. Kim ◽  
Shi Hoon Choi ◽  
Yeon Chul Yoo

This paper examines an effect of boron (B) on dynamic softening behavior, mechanical properties and microstructures for Nb-Ti added high strength interstitial free (IF) steel. For this purpose, IF steels containing 0ppm B, 5ppm B and 30ppm B were chosen. Continuous cooling compression test was performed to investigate dynamic softening behavior. Mechanical properties and microstructures of pilot hot-rolled IF steel sheet were analyzed by uni-axial tensile test and electron back-scattered diffraction (EBSD). It was found that no-dynamic recrystallization temperature (Tndrx) which can be determined from the relationship between flow stress and temperature is a constant of 955oC for all IF steels. However, an addition of B into IF steels increases work hardening rate at the temperature below Tndrx. It was also verified that B retards phase transformation of austenite into ferrite. EBSD analysis revealed that absence of B induces fine ferrite grain size and many high angle grain boundaries.


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