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"Recently, advanced technologies have put much attention on the materials selection as an alternative way to reduce the weight of material. Taking into account electronic devices, automobiles, aeronautics, and structural applications they are all required immense raw product. Magnesium and its alloys as one of the lightest metal (p = 1.8 g/m3) has attracted much intentions for an alternative metal alloy. Such good properties owned in magnesium including good castability, good machinability as well weldability and considerably cheap have made more convenient way for magnesium alloys to be used. However, its poor formability at room temperature is the major drawback of this material. Therefore, this project is intended to investigate the properties of AZ31 magnesium alloy especially for uniaxial tensile test at relatively low strain rate. Tensile properties were observed on the yield strength and elastic modulus which seems the crucial factor for magnesium tested at relatively low temperature. Slight dependency of plate orientations to the tensile properties for plate samples and tensile directions for sheet samples with three different sample thicknesses were also carried out. The experiment was done with the use of non-contact extensometer of Mini Instron Tensile Test.The main conclusion from the present study is that the thickness and the samples orientations affected tensile direction properties of the sheet samples. Microyielding occurred during the test which resulted in declining of modulus as the thickness increases. By contrast ultimate tensile strength, yield strength and ductility are generally increased as the thickness increased."

"This paper describes the material parameter determination procedure for the elastoviscoplastic bodner-partom model....."

"ABSTRAK3D Printing belakangan ini telah menjadi salah satu pilihan terbaik untuk memanufaktur suatu produk karena kemampuannya untuk menghasilkan bentuk yang kompleks dengan biaya yang tergolong murah. Selain itu, pemilihan material dalam proses manufaktur merupakan proses penting yang harus dilaksanakan. Dengan memadukan Thermoplastic Polyurethane (TPU) dan Polylactic Acid (PLA) filamen, diharapkan dapat menghasilkan material baru dengan properti yang lebih tinggi dibandingkan material aslinya. Kedua material ini tergolong sebagai material yang biodegradable dan biocompatible yang aman saat berhubungan langsung dengan makhluk hidup. Dibandingkan dengan Polylactic Acid, Thermoplastic Polyurethane memiliki elongation at break yang lebih tinggi. Jadi, dengan menggabungkan dua material ini menggunakan struktur komposit untuk metode 3D Printing yaitu sistem penguncian dengan mencetak material sisi demi sisi, material baru akan dihasilkan. Komposisi TPU dan PLA adalah TPU/PLA: 10%/90%; TPU/PLA: 20%/80%; TPU/PLA: 30%/70%; TPU/PLA: 35%/75%, TPU/PLA: 40%/60% secara berurutan. Properti mekanik dari material ini dinilai dari uji Tarik. Hasilnya adalah, Kekuatan Tarik: 45.42033 MPa, 44.73766 MPa, 50.03833 MPa, 48.7633 MPa, dan 51.0130 MPa untuk 10%, 20%, 30%, 35%, and 40% matrix material, berurutan. Elongasi: 18.71%, 16.33%, 17.06%, 16.93%, dan 17.09% untuk 10%, 20%, 30%, 35%, and 40% matrix material, berurutan. Modulus Elastisitas: 421.88 MPa, 420.19 MPa, 485.23 MPa, 462.22 MPa, dan 495.22 MPa untuk 10%, 20%, 30%, 35%, and 40% matrix material, berurutan. Kekuatan Yield: 44.81 MPa, 44.73 MPa, 50.03 MPa, 45.35 MPa, and 50.43 MPa untuk 10%, 20%, 30%, 35%, dan 40% matrix material, berurutan.

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ABSTRACT

3D Printing has become one of the best choices for manufacturing a product lately, due to its ability to produce a complex shape with an approximately low cost needed. On the other hand, material selection is always be an important step before doing any manufacturing process. By combining Thermoplastic Polyurethane and Polylactic Acid filament new material with higher properties than the original material is expected and can be one of the best choices of material to produce a medical related product. Both of these material are considered as a biodegradable and biocompatible material that is safe in contact with living issues. Thermoplastic Polyurethane has a higher elongation at break in compare to Polylactic Acid. So by combining these two material using a composite structure for 3D printing method which is the interlocking printing system by printing two different material side by side, a new material is produced. The Thermoplastic Polyurethane compositions are TPU/PLA: 10%/90%, TPU/PLA: 20%/80%, TPU/PLA: 30%/70%, TPU/PLA: 35%/75%, TPU/PLA: 40%/60% respectively. The mechanical properties of this new material were assessed by a tensile test. The results are Ultimate Tensile Strength 45.42033 MPa, 44.73766 MPa, 50.03833 MPa, 48.7633 MPa, and 51.0130 MPa for 10%, 20%, 30%, 35%, and 40% matrix material, respectively. Elongation at Break: 18.71%, 16.33%, 17.06%, 16.93%, and 17.09% for 10%, 20%, 30%, 35%, and 40% matrix material, respectively. Elastic Modulus: 421.88 MPa, 420.19 MPa, 485.23 MPa, 462.22 MPa, and 495.22 MPa for 10%, 20%, 30%, 35%, and 40% matrix material, respectively. Yield Strength: 44.81 MPa, 44.73 MPa, 50.03 MPa, 45.35 MPa, and 50.43 MPa for 10%, 20%, 30%, 35%, and 40% matrix material, respectively."

"The 7075 aluminum alloy (a typical Al–Zn–Mg–Cu alloy) is one of the most important engineering alloys. It is mainly used in the automotive industry, in transport and aeronautics, due to its excellent strength/weight ratio. The purpose of the present research is to model the behavior of 7075 aluminum alloy and to build an experimental database to identify the model parameters. Firstly, the paper presents an experimental device of simple tensile tests and the studied material on 7075 aluminum alloy. Thus, uniaxial tensile tests are carried out in three loading directions relative to the rolling direction. From experimental hardening curves and Lankford coefficients, the mechanical properties are extracted, particularly the various fractures owing to pronounced anisotropy relating to the material. Secondly, plastic anisotropy is then modeled using the identification strategy which depends on yield criteria, hardening and evolution laws. By smoothing experimental hardening curves in the tensile tests, a selection is made in order to choose the most appropriate hardening law for the identification of the studied material. Finally, a comparison with experimental data shows that the behavior model can successfully describe the anisotropy of the Lankford coefficient."

"Micro Friction Stir Spot Welding (m-FSSW) merupakan salah satu jenis solid state welding dengan menggunakan non-consumable tool ber-skala micro dengan ketebalan material <1 mm serta memanfaatkan gesekan dan axial force dalam prosesnya. Hasil dair pengelasan yaitu lap-joint pada satu titik. Pada penelitian ini dilakukan pengujian Geometri tool terhadap hasil pengelasan, sehingga didapatkan korelasi antara geometri tool, temperature, perubahan kecepatan putar, axial force, hasil uji tarik geser, dan uji micro dan macro. Pada eksperimen ini menggunakan 4 jenis tool yaitu, tool 1 (One stage shoulder 450), tool 2 (one stage shoulder 650), tool 3 (small taper), tool 4 (medium taper). Standar pengujian yang digunakan adalah ISO 14273 (Uji Tarik Geser) , ASTM E340 (Makrostruktur) , ASTM E407 (Mikrostruktur).  Pada eksperimen ini hasil uji tarik geser tertinggi yaitu 600,480 N dengan dwell time 4 detik dengan temperatur sekitar 321.5 ˚C terdapat pada tool 4 (Medium Taper). Pada hasil uji struktur makro dan mikro (crossection) terdapat daerah Stir Zone (SZ), Thermo-Mechanically Affected Zone (TMAZ), Heat Affected Zone (HAZ), Parent Metal (PM), Hook dan EXTD zone (pada tool 3 dan tool 4). Pada daerah SZ, terjadi rekristalisasi secara penuh (>220°C) sedangkan daerah TMAZ yang mengalami rekristalisasi sebagian akibat adanya panas dan mengalami perubahan sifat mekanik (120°C-250°C). dan untuk daerah HAZ atau daerah yang terpengaruhi panas namun tidak mengalami rekristalisasi (<220°C).  Pada pengujian Microstructure (crossection) menunjukkan Intermetallic Compound serta cacat yang ada dalam skala mikro dari sambungan pelat tipis AA1100 dan pelat tipis CuZn. Pada ekperimen ini terdapat pengaruh pada variasi dwell time terhadap geometry tool sehingga mempengaruhi distribusi temperatur, kecepatan putar, dan axial force yang mengakibatkan hasil kekuatan uji tarik geser meningkat dari dwell time 2s ke 4s, sedangkan mengalami penurunan pada dwell time 6s.

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Micro Friction Stir Spot Welding (m-FSSW) is a type of solid state welding using non-consumable micro-scale tools with a material thickness of <1 mm and utilizing friction and axial force in the process. The result of welding is a lap-joint at one point. In this research, tool geometry was tested on welding results, so that a correlation was obtained between tool geometry, temperature, changes in rotational speed, axial force, shear tensile test results, and micro and macro tests. In this experiment, 4 types of tools were used, namely, tool 1 (One stage shoulder 450), tool 2 (one stage shoulder 650), tool 3 (small taper), tool 4 (medium taper). The test standards used are ISO 14273 (Tensile Shear Test), ASTM E340 (Macrostructure), ASTM E407 (Microstructure). In this experiment, the highest shear tensile test result is 600,480 N with a dwell time of 4 seconds with a temperature of around 321.5 ˚C, was found on tool 4 (Medium Taper). In the macro and micro structure test results (crossection) there are Stir Zone (SZ), Thermo-Mechanically Affected Zone (TMAZ), Heat Affected Zone (HAZ), Parent Metal (PM), Hook and EXTD zones (on tool 3 and tool 4). In the SZ area, full recrystallization occurs (>220°C) while the TMAZ area experiences partial recrystallization due to heat and experiences changes in mechanical properties (120°C-250°C). and for HAZ areas or areas that are affected by heat but do not experience recrystallization (<220°C). The Microstructure (crossection) test shows the Intermetallic Compound and defects that exist on a micro scale from the joints of the AA1100 plate and the CuZn plate. In this experiment, there was an influence on variations in dwell time on the tool geometry, thus affecting the temperature distribution, rotational speed and axial force, which resulted in the shear tensile test strength results increasing from a dwell time of 2s to 4s, whereas it decreased at a dwell time of 6s."

"Micro Friction Stir Spot Welding (m-FSSW) merupakan salah satu jenis solid state welding dengan menggunakan non-consumable tool ber-skala mico thicknes material<1 mm) dan memanfaatkan gesekan serta axial force pada prosesnya. Hasil pengelasan yaitu lap-joint pada satu titik. Pada penelitian ini dilakukan pengujian Geometril tool terhadap hasil pengelasan, sehingga didapartkan korelasi antara geometri tool, temperature ,perubahan kecepaatn putar, hasil uji tarik geser dan uji hardness . Dimana semakin tinggi pin maka semakin tinggi RPM,temperature dan uji tarik (berbanding lurus) dimana ketinggian pin < plunge dept (600 µm). Namun Pada tool 4 geometri tool memiliki ketinggian pin 650 µm dan diameter 2.540 mm, sehingga membuat RPM masih di putaran tinggi ,temperatur pada suhu yang rendah dan hasil uji tarik yang belum maksimal (penetrasi hanya dilakukan di pin/Shoulder tidak menyentuk spesimen uji). Pada eksperimen ini peak temperatur tertinggi berada pada tool 3 (shoulder 450) dengan temperature 428.44˚C dengan hasil uji tarik geser yaitu 449.66 N (tertinggi). Pada pengujian tarik geser terdapat mode kegagalan diamati selama TS tes, yaitu mode PF (Pulled Out Nugget) pada seluruh hasil lasan dengan menggunakan tool 1 hingga tool 4. Hasil kekerasan pada geometri tool diketahui bahwa semakin tinggi pin maka hardnes akan semakin besar atau selaras dengan temperature yang terjadi. Namun saat temperatur berada pada suhu 400°C , material AA100 mengalami fully aneling sehingga berdampak pada penurunan hardness pada material hasil lasan (Jaehyung Cho ,2010). Pada hasil uji struktur makro (crossection) terdapat daerah Stir Zone (SZ), Thermo-Mechanically Affected Zone (TMAZ), Heat Affected Zone (HAZ),ParentMetal (PM), Hook dan EXTD zone (pada tool 1,2,3).Dimana daerah SZ (stir zone), terjadi rekristalisasi secara penuh (>350°C) sedangkan daerah TMAZ yang mengalami rekristalisasi sebagian akibat adanya panas dan mengalami perubahan sifat mekanik (250°C-350°C). dan untuk daerah HAZ atau daerah yang terpengaruhi panas namun

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Micro Friction Stir Spot Welding (m-FSSW) is a type of solid-state welding using a non-consumable tool with a mico scale (materialthickness < 1mm), using friction and axial force in the process. The result of welding is a lap joint at one point. This study has a correlation between tool geometry, temperature, rotational speed, tensile shear test, and hardness (Vickers) test. Where the higher the pin have higher the RPM, temperature, and tensile shear test (directly proportional) where the pin height < plunge depth (600 m). However, in tool 4 the geometry of the tool has a pin height of 650 m and a diameter of 2.54 mm so that the RPM is still at high rotation, the temperature is at a low temperature and the tensile shear results are not maximized (penetration is only at the pin/shoulder not touching the specimen). In this experiment, the highest peak temperature at tool 3 (shoulder 450) is about 428.44˚C with the results of the shear tensile test being 449.66 N (the highest). In the tensile shear test, get a failure mode, there is PF (Pulled Out Nugget) on all weld results (tools 1 to tool 4). The results of the hardness on the geometry of the tool are known that the higher pin, get the high hardness or proportional with the temperature that occurs. However, when the temperature is was at 400 °C, this material (AA100) had fully annealed and had an impact on decreasing the hardness of the welded material (Jaehyung Cho, 2010). In the macrostructure test results, there are Stir Zone (SZ), Thermo-Mechanically Affected Zone (TMAZ), Heat Affected Zone (HAZ), ParentMetal (PM), Hook, and EXTD zone (on tool 1,2,3). The SZ region (stir zone), where full recrystallization occurs (>350 °C) while the TMAZ region partially recrystallizes due to heat and changes in mechanical properties (250 °C-350 °C). and for the HAZ region or heat-affected region but not recrystallized (<250 °C)."

"Untuk mendapatkan kondisi regangan bidang pada uji tarik, modifikasi spesimen dilakukan. Modifikasi spesimen telah menunjukkan regangan minor yang bernilai nol untuk uji tarik yang dilakukan pada temperatur ruang sehingga kondisi regangan bidang dapat dicapai. Pengujian untuk kelayakan specimen dilanjutkan dengan melakukan uji tarik panas pada temperatur tinggi, untuk mengetahui apakah kondisi regangan bidang masih dapat dipertahankan pada temperatur tinggi. Material yang digunakan adalah baja HSLA ASTM A 572 grade 50. Selanjutnya, dilakukan pula pengamatan metalografi untuk mengamati perubahan mikrostruktur setelah uji tarik panas, yang dalam hal ini adalah ukuran butir ferrite. Hasilnya, untuk uji tarik panas yang dilakukan sampai 1,15 yield, kondisi regangan bidang dapat dipertahankan. Terkait dengan deformasi yang terjadi, didapat pula bahwa semakin besar reduksi ketebalan yang terjadi semakin halus butir ferrite.

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Modification of spesimen have done to get plane strain condition in tensile test. Modification of the specimens has shown zero minor strain on tensile test conducted at room temperature. Feasibility study of specimens followed by hot tensile testing at high temperatures, to determine whether plane strain condition can be maintained at high temperatures. The material used is a HSLA steel ASTM A 572 grade 50. Furthermore, metallographic observation has been conducted to get microstructure after hot tensile test, which the scope is ferrite grain size. Results, on hot tensile test is carried out until 1,15 yield point, plane strain condition can be maintained. Related to the deformation, it has found that the greater thickness reduction the finer ferrite grains that formed."

"Telah dilakukan penelitian untuk membuat material komposit sandwich dengan menggunakan epoxy dan lamina E-glass sebagai kulit dan polyurethane foam sebagai inti. Pembuatan material menggunakan metode Vacuum Assisted Resin Infusion (VARI), dan dibagi menjadi empat jenis material. Uji tarik dan uji tekan dilakukan untuk mengukur kekuatan mekanik material dan mengkarakterisasi jenis spesimen yang baik untuk digunakan dalam aplikasi kapal bersayap Wing in Surface Effect-8 (WiSE-8). Dari hasil pengujian didapatkan kekuatan mekanik terbaik dari panel III yang memiliki empat lapisan fiber dengan arah serat 0o, 90o, +45o, -45o dengan kuat tarik dan kuat tekan masing?masing bernilai 28,18 MPa 5,75 MPa. Kerusakan yang terjadi pada material berupa patahan yang dimulai dengan kegagalan pada inti dilanjutkan dengan kegagalan pada kulit akibat pengujian mekanik dilihat dengan menggunakan Scanning Electron Microscope (SEM).

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Sandwich composite materials consisting of epoxy and lamina E-glass as the facing layer dan polyurethane foam as the core layer. The materials were manufactured using a Vacuum Assisted Resing Infussion (VARI) method, the products were classified into four types of panels, panel I, II, III, and IV. Tensile and flextural tests applied to the materials to measure the mechanical strengths and to characterize whether is applicable for WiSE-8 application. The mechanical properties were obtained from panel III which consisted of four layers and a fibre direction of 0o, 90o,+45o, -45o. The tensile and flextural strengths were 28,18 MPa and 5,75 Mpa respectively. Scanning Electron Microscope (SEM) observation of the mechanical tested sampler showed that the failure of the materials started from the core and propagated to the facing layer."