scholarly journals Investigation of the phase transformation characteristics of Fe-Co elastrocalaric refrigeration alloy

2021 ◽  
Vol 2076 (1) ◽  
pp. 012033
Author(s):  
Xianfa Li ◽  
Yongjun Shi ◽  
Shuyao Wang
Keyword(s):  
Phase Transformation ◽  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Utilization Rate ◽  
Initial Ratio ◽  
Simple Process ◽  
Enthalpy Changes ◽  
Changing Trends ◽  
Material Utilization ◽  
Co Alloys

Abstract Mechanical alloying (AM) and powder metallurgy(PM) have been widely used in many fields especially in the development of new alloy materials due to the advantages of simple process, high material utilization rate and accurate material ratio. In this investigation, experimental procedures were proposed to explore the phase transformation characteristics, elastrocalaric refrigeration effect of Fe-Co alloys synthesized by AM and PM. The samples of Fe-Co elastrocalaric refrigeration alloy with different phase transformation temperatures and different enthalpy changes have been successfully prepared by changing the initial ratio of Co element. The results show that the phase transformation characteristics have changed with the increase of Co content and showed different changing trends.

scholarly journals The effect of milling time on the alumina phase transformation in the AMCs powder metallurgy reinforced by silica-sand-tailings

2022 ◽  
pp. 103-117
Author(s):  
Sukanto ◽  
Wahyono Suprapto ◽  
Rudy Soenoko ◽  
Yudy Surya Irawan
Keyword(s):  
Particle Size ◽  
Phase Transformation ◽  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Milling Time ◽  
Sintering Temperature ◽  
Silica Sand ◽  
Second Phase ◽  
The Matrix ◽  
The Impact

This study aims to determine the effect of milling time and sintering temperature parameters on the alumina transformation phase in the manufacture of Aluminium Matrix Composites (AMCs) reinforced by 20 % silica sand tailings using powder metallurgy technology. The matrix and fillers use waste to make the composites more efficient, clean the environment, and increase waste utilization. The milling time applied to the Mechanical Alloying (MA) process was 0.5, 6, 24, 48, and 96 hours, with a ball parameter ratio of 15:1 and a rotation of 93 rpm. Furthermore, hot compaction was carried out using a 100 MPa two-way hydraulic compression machine at a temperature of 300 °C for 20 minutes. The temperature variables of the sintering parameter process were 550, 600 to 650 °C, with a holding time of 10 minutes. Characterization of materials carried out included testing particle size, porosity, X-Ray Diffraction (XRD), SEM-Image, and SEM-EDX. The particle measurement of mechanical alloying processed, using Particle Size Analyzer (PSA) instrument and based on XRD data using the Scherrer equation, showed a relatively similar trend, decreasing particle size occurs when milling time was increased 0.5 to 24 hours. However, when the milling time increases to 48 and 96 hours, the particle size tends to increase slightly, due to cold-weld and agglomeration when the Mechanical Alloying is processed. The impact is the occurrence of the matrix and filler particle pairs in the cold-weld state. So, the results of XRD and SEM-EDX characterization showed a second phase transformation to form alumina compounds at a relatively low sintering temperature of 600 °C after the mechanical alloying process was carried out with a milling time on least 24 hours

Preparation of Cu-Cr-Zr/AlN Nanocomposites and their Mechanical and Conductive Properties

2011 ◽  
Vol 239-242 ◽  
pp. 2756-2759
Author(s):  
Yong Qiang Qin ◽  
Yu Cheng Wu ◽  
Yan Wang ◽  
Yu Hong ◽  
Jing Quan Deng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Room Temperature ◽  
Copper Alloys ◽  
Morphology Characterization ◽  
Conductive Properties ◽  
Conductivity Behavior

Copper and copper alloys had various applications in tremendous areas due to their unique properties, such as good conductivity, good thermal conductivity and so on. However, applications of copper and copper alloys were severely restricted as the result of the limited strength at room temperature and poor wear-resistance at high temperature. In this paper, we investigated the preparation of Cu-Cr-Zr/AlN nanocomposites by mechanical alloying process and then powder metallurgy technology. XRD and SEM were performed for the phase and morphology characterization. The conductivity properties were also tested and the results showed that Cu-Cr-Zr/AlN nanocomposites exhibited excellent conductivity behavior.

Analysis of tribological properties of graphite and aluminum composite materials prepared by powder metallurgy technique

2020 ◽  
Vol 10 (5) ◽  
pp. 663-670
Author(s):  
Zhigang Wang ◽  
Jun Li ◽  
Daquan Li
Keyword(s):  
Composite Materials ◽  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Tribological Properties ◽  
Utilization Rate ◽  
Powder Metallurgy Technique ◽  
Aluminum Composite ◽  
Powder Metallurgy Process ◽  
Metallurgy Process ◽  
Composite Samples

In order to make full use of the wear resistance and antifriction of the mixed reinforced particles, improve the performance and utilization rate of the composite material, and reduce its wear amount, in this study, graphite and aluminum composite materials with different graphite concentration were prepared by powder metallurgy process. On this basis, the influence of different graphite concentration on the friction coefficient and wear amount of composite samples and different load on the wear amount of composite materials were discussed and analyzed. The results show that with the increase of graphite content, the friction coefficient and wear amount of the composite will decrease correspondingly. When the load is less than 30 N, the wear curve of the sample changes steadily. When the load is more than 30 N, the wear will increase sharply. Therefore, the analysis of the tribological properties of the graphite and aluminum composites based on the powder metallurgy process plays an important role in improving the utilization rate of the composite and reducing its wear.

Compression stress strengthening modelling of a ultrafine-grained equiatomic SPS CoCrFeNiNb high-entropy alloy

2020 ◽  
pp. 095440622094324
Author(s):  
Marcello Cabibbo ◽  
Filip Průša ◽  
Alexandra Šenková ◽  
Andrea Školáková ◽  
Vojtěch Kučera ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Oxide Phase ◽  
High Entropy Alloy ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

High-entropy alloys are known to show exceptionally high mechanical properties, both compression and tensile strength, and unique physical properties, such as their phase stability. These quite unusual properties are primarily due to the microstructure generated by mechanical alloying processes, such as conventional induction arc melting, powder metallurgy, or mechanical alloying. In the present study, an equiatomic CoCrFeNiNb high-entropy alloy was prepared by a sequence of conventional induction melting, powder metallurgy, and compaction via spark plasma sintering. The high-entropy alloys showed uniform sub-micrometer grain microstructure consisted by a mixture of an fcc solid solution strengthened by a hcp Laves phase and a third intergranular oxide phase. The as-cast high-entropy alloys showed an ultimate compression strength (UCS) of ∼1400 MPa, which after sintering and compaction at 1273 K increased up to ∼2400 MPa. Extensive transmission electron microscopy quantitative analyses were carried out to model the UCS. A quite good agreement between the microstructure-strengthening model and the experimental UCS was found.

The Mechanical Behavior Analyses and Optimization on Large Wind Turbine Frustum Tower Structure

2013 ◽  
Vol 351-352 ◽  
pp. 270-274
Author(s):  
Chun Yan Gao ◽  
Zhao Yu Gong ◽  
Bin Li
Keyword(s):  
Wind Turbine ◽  
Fem Analysis ◽  
Utilization Rate ◽  
Finite Element Program ◽  
Model Calculations ◽  
Tower Structure ◽  
Element Program ◽  
Strength And Stiffness ◽  
Material Utilization ◽  
Large Wind

At present, frustum tower is widely used in the large wind turbine on the international wind electric market, which is a typical high drumstick and dumbbell type high-rise structure, whose mechanical characteristics and design methods have some particularity. In this paper, using the finite element program SAP2000, the primary selection tower was carried on the static strength and stiffness analyses, some control indexes which affect the tower design were studied. Based on the FEM analysis results, combining with a great deal of model calculations, this kind of tower were optimized. Research results show that the material utilization rate of wind turbine tower is low, and that the top displacement and stiffness of the tower is the controlling factors of design. Based on the optimization results, a new tower with straight lower part and frustum upper part is proposed, which can increase stiffness of tower, improve the material utilization, and reduce the overall steel amount of tower.

scholarly journals Phase Transformation Control of Powder Metallurgy Super-Elastic Ti–Ni Alloy by Adding Co Element

2019 ◽  
Vol 60 (8) ◽  
pp. 1583-1590
Author(s):  
Tomoki Eda ◽  
Anak Khantachawana ◽  
Junko Umeda ◽  
Katsuyoshi Kondoh
Keyword(s):  
Phase Transformation ◽  
Powder Metallurgy ◽  
Ni Alloy
Sign in / Sign up

Export Citation Format

Share Document