scholarly journals PENGARUH PENINGKATAN % REDUKSI TERHADAP PENGHALUSAN BUTIR DAN SIFAT MEKANIK PADUAN Cu-Zn 70/30 SETELAH DEFORMASI PADA SUHU 400°C

2016 ◽  
Vol 10 (3) ◽  
pp. 163-172
Author(s):  
Eka Febriyanti ◽  
Amin Suhadi ◽  
Rini Riastuti ◽  
Dedi Priadi

 Paduan Cu-Zn 70/30 banyak digunakan dalam berbagai aplikasi industri karena memiliki sifat yang unggul dan belum ada penggantinya. Untuk memperoleh paduan Cu-Zn 70/30 dengan sifat mekanik yang tinggi maka dilakukan riset baik modifikasi dari jenis material yang sudah ada ataupun material baru agar sesuai dengan kebutuhan industri. Untuk mengurangi biaya produksi, namun tetap menghasilkan sifat mekanik yang baik tanpa penambahan paduan maka dikembangkan metode penghalusan butir. Salah satu alternatif proses fabrikasi untuk mengoptimalkan sifat mekanik paduan Cu-Zn 70/30 yaitu dengan metode warm rolling. Warm rolling yang dilakukan pada pelat paduan Cu-Zn 70/30 menggunakan % reduksi sebanyak 29,03%, 34,4%, dan 38,16% pada suhu 400°C secara double pass reversible. Untuk paduan Cu-Zn 70/30, rentang pengerjaan warm rolling berada pada suhu 0,4 s/d 0,6 Tm (melting point) yaitu berkisar antara 382°C-573°C. Hasil metalografi didapat ukuran butir yang semakin menurun sebesar 30,03 µm di bagian tepi dan 33,45 µm di bagian tengah pada % reduksi 38,16%. Hasil uji tarik dengan % reduksi 38,16% menghasilkan nilai ultimate tensile strength (UTS) sebesar 478 MPa, yield strength (YS) sebesar 434 MPa, dan persentase elongasi sebesar 9%. Untuk hasil uji kekerasan menghasilkan nilai kekerasan sebesar 135,8 HV di bagian tepi dan 128,4 HV di bagian tengah pada % reduksi 38,16%. 

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Ayu Rizeki Ridhowati ◽  
Eka Febriyanti ◽  
Rini Riastuti

Warm rolling is one of the thermomechanical method has several advantages such as produces high mechanical properties, but does not decrease % elongation and toughness value because partial recrystallization phenomenon that produces micron-sized new grain. This paper reports the results of an investigation carried out on the effects of holding time annealing to mechanical properties Cu-Zn 70/30 alloy. These alloy after homogenization process and quenched in the air then heated to temperature of 300°C, later the heated copper samples are warm rolled at 25%, 30%, and 35% reduction, after that heated at temperature 300°C and held during 120 minutes. Then sample is experienced rewarm rolling with reduction 25%, 30%, and 35%. The results obtained showed that the ultimate tensile strength and yield strength are higher proportional with the increasing of % reduction, their values are 501,1 MPa; 599,3 MPa; later decrease to 546, 5 MPa and to yield strength are 441,8 MPa; 466,1 MPa; then decrease to 458,6 MPa. Moreover hardness value increase proportional with % reduction such as 154 HV; 162 HV; after that decrease to 160 HV While, % elongation decreases inversely proportional with % reduction namely 12,4%; 8,2%; later increase to 11,2 %. It is caused of the partial recrystallization phenomenon as evidenced by the presence micron-sized.AbstrakWarm rolling merupakan salah satu metode termomekanik yang mempunyai beberapa keuntungan yaitu salah satunya menghasilkan sifat mekanik yang tinggi, namun tidak mengurunkan nilai keuletan karena adanya fenomena rekristalisasi parsial yang menghasilkan butiran baru berbentuk micron. Paper ini menjelaskan tentang hasil penelitian berupa pengaruh persentase reduksi terhadap sifat mekanis paduan Cu-Zn 70/30. Paduan Cu-Zn 70/30 setelah dilakukan proses homogenisasi dan didinginkan di udara lalu dipanaskan ke suhu 300°C, kemudian masing-masing dilakukan warm rolling dengan persentase reduksi sebesar 25%, 30%, dan 35% kemudian ditahan di suhu 300°C dalam waktu 120 menit. Selanjutnya sampel dilakukan rewarm rolling dengan persentase reduksi sebesar 25%, 30%, dan 35%. Hasil penelitian yang dilakukan antara lain nilai kekuatan tarik (UTS dan YS) yang semakin tinggi sebanding dengan peningkatan % reduksi warm rolling yaitu masing-masing untuk nilai UTS sebesar 501,1 MPa; 599,3 MPa; lalu menurun menjadi 546,5 MPa serta untuk nilai kekuatan luluh sebesar 441,8 MPa; 466,1 MPa; lalu menurun menjadi 458,6 MPa. Selain itu, nilai kekerasan meningkat sebanding dengan peningkatan % reduksi warm rolling masing-masing sebesar 154 HV; 162 HV; lalu menurun menjadi 160 HV. Sedangkan persentase elongasi semakin menurun berbanding terbalik dengan peningkatan % reduksi masing-masing sebesar 12,4%; 8,2%; lalu meningkat menjadi 11,2%. Hal tersebut disebabkan karena adanya fenomena rekristalisasi parsial yang dibuktikan dengan kehadiran butir kecil berukuran mikron.Keywords : Cu-Zn 70/30 alloy, warm rolling, anneal, % reduction, mechanical properties


2019 ◽  
Vol 15 (2) ◽  
pp. 29
Author(s):  
Eka Febriyanti ◽  
Rini Riastuti

Abstract Warm rolling is one of the thermomechanical method has several advantages such as produces high mechanical properties, but does not decrease % elongation and toughness value because partial recrystallization phenomenon that produces micron-sized new grain. This paper reports the results of an investigation carried out on the effects of holding time annealing to mechanical properties Cu-Zn 70/30 alloy. These alloy after homogenization process and quenched in the air then heated to temperature of 300°C, later the heated copper samples are warm rolled at 25%, 30%, and 35% reduction, after that heated at temperature 300°C and held during 120 minutes. Then sample is experienced rewarm rolling with reduction 25%, 30%, and 35%. The results obtained showed that the ultimate tensile strength and yield strength are higher proportional with the increasing of % reduction, their values are 501,1 MPa; 599,3 MPa; later decrease to 546, 5 MPa and to yield strength are 441,8 MPa; 466,1 MPa; then decrease to 458,6 MPa. Moreover hardness value increase proportional with % reduction such as 154 HV; 162 HV; after that decrease to 160 HV While, % elongation decreases inversely proportional with % reduction namely 12,4%; 8,2%; later increase to 11,2 %. It is caused of the partial recrystallization phenomenon as evidenced by the presence micron-sized. Warm rolling merupakan salah satu metode termomekanik yang mempunyai beberapa keuntungan yaitu salah satunya menghasilkan sifat mekanik yang tinggi, namun tidak mengurunkan nilai keuletan karena adanya fenomena rekristalisasi parsial yang menghasilkan butiran baru berbentuk micron. Paper ini menjelaskan tentang hasil penelitian berupa pengaruh persentase reduksi terhadap sifat mekanis paduan Cu-Zn 70/30. Paduan Cu-Zn 70/30 setelah dilakukan proses homogenisasi dan didinginkan di udara lalu dipanaskan ke suhu 300°C, kemudian masing-masing dilakukan warm rolling dengan persentase reduksi sebesar 25%, 30%, dan 35% kemudian ditahan di suhu 300°C dalam waktu 120 menit. Selanjutnya sampel dilakukan rewarm rolling dengan persentase reduksi sebesar 25%, 30%, dan 35%. Hasil penelitian yang dilakukan antara lain nilai kekuatan tarik (UTS dan YS) yang semakin tinggi sebanding dengan peningkatan % reduksi warm rolling yaitu masing-masing untuk nilai UTS sebesar 501,1 MPa; 599,3 MPa; lalu menurun menjadi 546,5 MPa serta untuk nilai kekuatan luluh sebesar 441,8 MPa; 466,1 MPa; lalu menurun menjadi 458,6 MPa. Selain itu, nilai kekerasan meningkat sebanding dengan peningkatan % reduksi warm rolling masing-masing sebesar 154 HV; 162 HV; lalu menurun menjadi 160 HV. Sedangkan persentase elongasi semakin menurun berbanding terbalik dengan peningkatan % reduksi masing-masing sebesar 12,4%; 8,2%; lalu meningkat menjadi 11,2%. Hal tersebut disebabkan karena adanya fenomena rekristalisasi parsial yang dibuktikan dengan kehadiran butir kecil berukuran mikron. Keywords:Cu-Zn 70/30 alloy, warm rolling, anneal, % reduction, mechanical properties 


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Hongxin Liao ◽  
Taekyung Lee ◽  
Jiangfeng Song ◽  
Jonghyun Kim ◽  
Fusheng Pan

The microstructures and mechanical properties of the Mg88.5Zn5Y6.5-XREX (RE = Yb and Ce, X = 0, 1.5, 3.0, and 4.5) (wt.%) alloys were investigated in the present study. Mg88.5Zn5Y6.5 is composed of three phases, namely, α-Mg, long-period stacking ordered (LPSO) phases, and intermetallic compounds. The content of the LPSO phases decreased with the addition of Ce and Yb, and no LPSO phases were detected in Mg88.5Zn5Y2.0Yb4.5. The alloys containing the LPSO phases possessed a stratified microstructure and exhibited excellent mechanical properties. Mg88.5Zn5Y5.0Ce1.5 exhibited the highest creep resistance and mechanical strength at both room temperature and 200 °C, owing to its suitable microstructure and high thermal stability. The yield strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature was 358 MPa. The ultimate tensile strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature and 200 °C was 453 MPa and 360 MPa, respectively.


Author(s):  
Aleksandr B. VOROZHTSOV ◽  
◽  
Vladimir V. PLATOV ◽  
Aleksandr A. KOZULIN ◽  
Anton P. KHRUSTALEV ◽  
...  

In this work, the special master alloys containing aluminum and TiB2 powder with bimodal particle size distribution in three mixture compositions are prepared. The master alloys are infused into the melts using an external ultrasound source. The castings with particles had smaller grain sizes than the initial castings without particles. It is found that the hardness, yield strength, and ultimate tensile strength reach higher values with an increase in the relative elongation of the cast alloys with added particles. A warm rolling mode is employed for the studied alloys to obtain sheet blanks. It is shown that the staged shrinkage of the billets up to deformation of 80 % with periodic heating up to 300 °C allows one to obtain defect-free sheet products. The structure of the rolled sheet-alloys is characterized by the plate-shaped grains elongated along the rolling direction with pockets of submicron-sized grains in between. The strength properties of the studied rolled alloys exceeded those of the cast alloys. In the case of the rolled alloys, an increase in the yield strength, ultimate tensile strength, and ductility is revealed for the alloys with particles as compared to the ones with no particles added.


2019 ◽  
Vol 22 (2) ◽  
pp. 143-150
Author(s):  
Hussain J. M. Al-Alkawi ◽  
Abduljabbar Owaid Hanfesh ◽  
Saja Mohammed Noori Mohammed Rauof

This research is devoted to study the influence of different weight percent concerning to the additions of Ti and Cu on mechanical and tribological properties of AA6061. The composite materials consist of different weight percentage of Ti (0.2, 0.4, and 0.6) wt% and constant weight percentage of Cu (0.2) wt% which were fabricated by liquid metallurgy route technique. Microstructural characterization and phases have been examined by using SEM (scanning electron microscopic).SEM examination showed uniform distribution of nano Ti and Cu in AA6061. The consequences of mechanical tests demonstrated clear enhancement in mechanical properties, such as ultimate tensile strength, yield strength, young modulus, ductility% and hardness at additive percentage of 0.4% Ti+0.2%Cu nano particles incorporated into molten AA6061. Percentage of enhancement ultimate tensile strength is about 73.3%, yield strength about 82.7%, young modulus is about 21.2%, the  Vickers hardness about 42.6% and the decreasing in ductility was about 25.2% compared with the metal matrix (AA6061). The wear rate test was performed by using pin on disc rig for both hybrid nano composite and base metal (AA6061) under various loads (10,15and 20) N with sliding speed (1.282) m/sec at a (10) min’s time. The results showed a decrease in wear rate at 0.4%Ti+0.2%Cu compared with the base metal (AA6061). Improvement percentage of wear rate is about 105% at 20 N load.


2019 ◽  
Vol 8 (2S8) ◽  
pp. 1027-1032

Nano technology has fascinated the attention of numerous material scientists and design engineers. The nano scaled particulates incorporation exhibit many attractive and special properties. The inclusion of nano particulates into the copper matrix might augments the hardness, ultimate tensile strength and yield strength significantly increases, maintaining the ductility. In this paper, the nano Al2O3 reinforced copper - 5%tin- metal matrix composites were manufactured by stir casting technique and reinforcement is varied from 0wt. % to 9wt. % in ventures of 3wt. %. The nano composites are characterized in terms of their mechanical and wear properties. Results revealed that, the distribution of nano Al2O3 particulates is fairly uniform in copper - 5%tin metal matrix. As the level of reinforcement increases, hardness, yield strength, ultimate tensile strength, and wear resistance of the copper - 5%tin – nano Al2O3 metal matrix composites increases. The developed nano metal matrix composites may be an alternative material for bearing applications


2004 ◽  
Vol 449-452 ◽  
pp. 305-308
Author(s):  
Lei Wang ◽  
Toshiro Kobayashi ◽  
Chun Ming Liu

Tensile test at loading velocities up to 10 m·s-1(strain rate up to 3.2x102s-1) was carried out forr SiCp/AC4CH composite and AC4CH alloy. The microstructure of the composite before and after tensile deformation was carefully examined with both optical microscope and SEM. The experimental results demonstrated that the ultimate tensile strength (UTS) and yield strength (YS) increase with increasing loading velocity up to 10 m·s-1. Comparing with AC4CH alloy, the fracture elongation of the composite is sensitivity with the increasing strain rate. The YS of both the composite and AC4CH alloy shows more sensitive than that of the UTS with the increasing strain rate, especially in the range of strain rate higher than 102s-1.


2004 ◽  
pp. 133-173

Abstract This data set presents aging response curves for a wide range of aluminum casting alloys. The aging response curves are of two types: room-temperature, or "natural," curves and artificial, or "high-temperature," curves. The curves in each group are presented in the numeric sequence of the casting alloy designation. The curves included are the results of measurements on individual lots considered representative of the respective alloys and tempers. The properties considered are yield strength, ultimate tensile strength, elongation, and Brinell hardness.


2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Mohd Shukor Salleh ◽  
Nurul Naili Mohamad Ishak ◽  
Saifudin Hafiz Yahaya

In this study, the effect of different amounts of copper (CU) on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg (x= 3, 4 and 5, mass fraction, %) were investigated. The alloys were prepared via cooling slope casting technique, before there were thixoformed using compression press. All of the alloys were then characterized using optical microscope (OM), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results obtained revealed that cooling slope casting produced a non-dendritic microstructure and the intermetallic phase in the thixoformed samples was refined and evenly distributed. The results also revealed that as the Cu content in the alloy increases, the hardness and tensile strength of the thixoformed alloys also increase. The hardness of thixoformed Al-6Si-3Cu was 104.1 HV while the hardness of Al-6Si-5Cu alloy was increased to 118.2 HV. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed alloy which contained 3wt.% Cu were 241 MPa, 176 MPa and 3.2% respectively. The ultimate tensile strength, yield strength and elongation to fracture of the alloy that contained 6wt.% of Cu were 280 MPa, 238 MPa and 1.2% respectively. The fracture surface of the tensile sample with lower Cu content exhibited dimple rupture while higher Cu content showed a cleavage fracture.


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