Influence Study of the Plastic Deformation Mode on the Micro-Indentation Mechanical Properties for the Pure Molybdenum

2021 ◽  
Vol 894 ◽  
pp. 39-43
Author(s):  
Jiang Li ◽  
Peng Fa Feng ◽  
Fu Guo Li ◽  
Qing Hua Li ◽  
Lin Lin Duan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Powder Metallurgy ◽  
Deformation Mode ◽  
Indentation Hardness ◽  
Pure Molybdenum ◽  
Apparent Modulus ◽  
Deformation Instability ◽  
Deformation Modes ◽  
Micro Indentation

Four different plastic deformation modes of pure molybdenum in powder metallurgy were studied, including single tensile, single torsion, tensile-torsion and compressive-torsion. Then the influence of these four plastic deformation modes on the micro-mechanical properties of pure molybdenum in powder metallurgy was studied by the micro-indentation method. The results show that the accumulated strain before deformation instability or fracture of the studied material caused by different plastic deformation modes is different, while showing a regular variation. And the mean indentation hardness along the radial direction of the sample also change regularly, which results in different strengthening effects on the molybdenum material itself. The damage inside the deformed material will cause the apparent modulus of elasticity measured by micro-indentation to decrease significantly.

Microstructure Evolution and Deformation Mechanisms of Harmonic Structure Designed Materials

2016 ◽  
Vol 879 ◽  
pp. 145-150
Author(s):  
Kei Ameyama ◽  
Sanjay Kumar Vajpai ◽  
Mie Ota
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Powder Metallurgy ◽  
Early Stage ◽  
High Strength ◽  
Plastic Instability ◽  
Structure Design ◽  
Harmonic Structure ◽  
Homogeneous Microstructure ◽  
Macro Scale

This paper presents the novel microstructure design, called Harmonic Structure, which gives structural metallic materials outstanding mechanical properties through an innovative powder metallurgy process. Homogeneous and ultra-fine grain (UFG) structure enables the materials high strength. However, such a “Homo-“ and “UFG” microstructure does not, usually, satisfy the need to be both strong and ductile, due to the plastic instability in the early stage of the deformation. As opposed to such a “Homo-and UFG“ microstructure, “Harmonic Structure” has a heterogeneous microstructure consisting of bimodal grain size together with a controlled and specific topological distribution of fine and coarse grains. In other words, the harmonic structure is heterogeneous on micro-but homogeneous on macro-scales. In the present work, the harmonic structure design has been applied to pure metals and alloys via a powder metallurgy route consisting of controlled severe plastic deformation of the corresponding powders by mechanical milling or high pressure gas milling, and subsequent consolidation by SPS. At a macro-scale, the harmonic structure materials exhibited superior combination of strength and ductility as compared to their homogeneous microstructure counterparts. This behavior was essentially related to the ability of the harmonic structure to promote the uniform distribution of strain during plastic deformation, leading to improved mechanical properties by avoiding or delaying localized plastic instability.

Polarization of plastic deformation modes in polysynthetically twinned TiAl crystals

2003 ◽  
Vol 18 (3) ◽  
pp. 702-708 ◽  
Author(s):  
V. Paidar ◽  
K. Kishida ◽  
M. Yamaguchi
Keyword(s):  
Plastic Deformation ◽  
Deformation Mode ◽  
Deformation Twinning ◽  
Additional Stress ◽  
Burgers Vector ◽  
Stress Increase ◽  
Loading Direction ◽  
Deformation Modes ◽  
Lamellar Interfaces

Polarization of deformation twinning (its propagation in a certain sense but not in the opposite one) is taken for granted. However, the same phenomenon can occur for a superdislocation glide as well, as is demonstrated in this paper. The consequences for plastic deformation of polysynthetically twinned TiAl crystals with the lamellar interfaces parallel to the loading direction are discussed. It is not the interface itself that is an obstacle for propagating deformation but also the fact that a deformation mode with the parallel Burgers vector cannot be activated in the neighboring lamella due to the directionality of superdislocation motion leading to additional stress increase.

Characterization and Properties of Copper-Silica Sand Nanoparticle Composites

2011 ◽  
Vol 319-320 ◽  
pp. 95-105 ◽  
Author(s):  
Tahir Ahmad ◽  
Othman Mamat
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Plastic Deformation ◽  
Powder Metallurgy ◽  
Silica Sand ◽  
Prealloyed Powder ◽  
Powder Metallurgy Process ◽  
Rearrangement Mechanism ◽  
Nanoparticle Composites ◽  
Metallurgy Process

Copper-based microcomposites fabricated by powder metallurgy with subsequent plastic deformation have received increasing attention over recent years. These microcomposites possess good electrical conductivity in combination with high mechanical properties. The present study aims to explore potential technical merits in developing a prealloyed powder metallurgy copper based composites with silica sand nanoparticles reinforcement. Relevant mechanical properties and electrical conductivity improvements are the main targets. A copper based composite with 5, 10, 15 and 20 wt.% of silica sand nanoparticles were developed through the powder metallurgy process. It was observed that by addition of silica sand nanoparticles with 20% increased the hardness up to 143HV. Optimum electrical conductivity of the composites was achieved in the 15 wt.% silica sand nanoparticles. Advanced particle rearrangement mechanism due to homogeneous and fine distribution of silica sand nanoparticles into pore sites of the composites was also observed. The silica sand nanoparticles composites properties that are much more surface-related seen to be improved convincingly compared with the bulk controlled.

scholarly journals Microstructure and Mechanical Properties of Friction Stir Welded Joint of an Aluminum Alloy Sheet 6005A-T4

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1152 ◽  
Author(s):  
Xiaofei Sheng ◽  
Kai Li ◽  
Wenke Wu ◽  
Yong Yang ◽  
Yu Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Alloy Sheet ◽  
Welding Parameters ◽  
Indentation Hardness ◽  
Related Field ◽  
Friction Stir ◽  
Β Phase ◽  
Fine Grain ◽  
Equiaxed Grain ◽  
Micro Indentation

The 6005A-T6 alloy had been widely applied in rail transmit industry due to its combination properties of moderate strength, superior resistance to corrosion, and excellent extrusion plasticity. However, few reports were related to the 6005A-T4 alloy in spite of it also presenting considerable properties. In this work, we introduced the FSW method to investigate the weldability and mechanical properties of a thin plate aluminum 6005A-T4 to evaluate its potential application. Fully recrystallized microstructure was obtained in the nugget zone, characterized by equiaxed grain with a size of 2.2 μm under current welding parameters. The tensile strength can reach as high as 174 ± 2 MPa with the absence of β phase, which is equivalent to 83.8% of that of base metal. The dissolution of β phase will dramatically reduce the micro-indentation hardness down to as low as 58 HV0.2 and the fine grain, for example 2 μm in this work, will reversely raise this value up to 64 HV0.2. Our investigation provides some perspectives to understand weldability, mechanical properties of the 6005A-T4 alloy, and develop its further applications in the related field.

Irradiation of Polyamide Measured by Micro-Indentation Test

2015 ◽  
Vol 1120-1121 ◽  
pp. 1179-1182
Author(s):  
Martin Ovsik ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
Adam Skrobak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Material Properties ◽  
Indentation Test ◽  
Polymer Chains ◽  
Cross Linking ◽  
Indentation Hardness ◽  
Chemical Bonds ◽  
Depth Sensing ◽  
Micro Indentation

Cross-linking is a process in which polymer chains are associated through chemical bonds. This research paper deals with the possible utilization of irradiated polyamide. Influence of the intensity of irradiation on micro-indentation hardness was investigated. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of micro-indentation test shows increasing in micro-mechanical properties of surface layer. The highest values of micro-mechanical properties were reached radiation dose of 99 kGy, when the micro-mechanical values increased by about 18%.

Mechanical Properties of Fine-Grained AA1050 after ECAP

2006 ◽  
Vol 503-504 ◽  
pp. 847-852 ◽  
Author(s):  
Stijn Poortmans ◽  
Bert Verlinden
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Room Temperature ◽  
Deformation Mode ◽  
Fine Grained ◽  
Tension Tests ◽  
Hot Rolled ◽  
Deformation Tests ◽  
Deformation Modes ◽  
Cylindrical Samples

The mechanical properties of fine-grained Aluminium AA1050 produced by ECAP at room temperature, have been investigated under various deformation modes. Because ECAP leads to an unstable microstructure, some samples were annealed at 300°C for 10 minutes in order to stabilise the microstructure. For mechanical testing, cylindrical samples were used in three types of monotonic deformation tests: axisymmetric compression, uniaxial tension and simple shear by torsion. The influence of the deformation mode on the yield locus and strain hardening behaviour has been studied and will be discussed for both hot rolled AA1050, ECAP samples without annealing and annealed ECAP samples. To achieve a better understanding of the strain hardening, some preliminary tests with a change in strain path were also performed. The results of tension tests followed by compression will be reported.

New Design of Aluminium Based Composites through Combined Method of Powder Metallurgy and Thixoforming

2014 ◽  
Vol 939 ◽  
pp. 68-75 ◽  
Author(s):  
Lygia Maria Policarpio Ferreira ◽  
Maria Helena Robert ◽  
Emin Bayraktar ◽  
Diana Zaimova
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
High Energy ◽  
Raw Material ◽  
Combined Method ◽  
Indentation Tests ◽  
Metal Chips ◽  
Aeronautical Industry ◽  
Semi Solid ◽  
Micro Indentation

The present study deals with a new design of aluminium alloy based composites reinforced with SiC particles and Si/Al2O3 powders through combined methods of powder metallurgy and thixoforming. Moreover, recycled machining chips are used as raw material, specifically AA7075 chips generated in the aeronautical industry. The proposed method is based on forming at high temperatures a compacted mixture of metal chips and reinforcing particles, with the metal in thixotropic semi-solid condition. Composites containing different SiC weight fractions (10, 20 and 30%) were produced and had their microstructure analyzed. Mechanical properties were evaluated by means of micro-indentation tests. General results show the feasibility of producing composites by the proposed route. Products with good mechanical properties could be obtained. The process, even still not completely optimized as some improvement still must be achieved, can bring a new possibility for the production of a noble material from recycled wastes, particularly important in the high energy spending Al industries.

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