scholarly journals Correlation between the Microstructure and Mechanical Properties of W-Bearing Ti-6Al-4V Alloys

2021 ◽  
Vol 59 (6) ◽  
pp. 357-364
Author(s):  
Godwin Kwame Ahiale ◽  
In-Seok Kye ◽  
Young Sam Kwon ◽  
Yong-Jun Oh
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Solid Solution Hardening ◽  
Powder Injection ◽  
Injection Molding Process ◽  
Molding Process ◽  
Β Phase ◽  
Α Phase ◽  
The Matrix ◽  
Indentation Tests

W-containing Ti-6Al-4V alloys (W=0, 1, and 5 wt%) were fabricated by the powder injection molding process, and the corresponding effects of tungsten content on the mechanical properties and microstructure of the alloys were investigated. The alloy powders were sintered at 1200 °C and then hot-isostatically-pressed at 900 °C. The fabricated alloys were subjected to microstructural and chemical analyses, and tensile and nano-indentation tests. The yield strength and tensile strength proportionally increased as the W content was increased from 0 wt% to 5 wt%. Ductility was not affected by the addition of up to 5 wt% W due to its complete dissolution in the matrix. Higher W addition induced finer α/β lamellar microstructures and increased the β to α phase ratio. Moreover, the added W dissolved preferentially in the β phase by solid solution hardening, increasing the hardness of the β phase, which originally was significantly softer than the α phase. For the alloys containing up to 5 wt% W, the strengthening without ductility loss was attributed to the finer α/β lamellae and the volume increase in the β phase hardened by W. These results suggest that adding W to Ti-6Al-4V alloy is a promising method for developing Ti alloys with both high strength and toughness.

Microstructure and Mechanical Properties of Metal Injection Molded SiCP/ Cu Composites

2012 ◽  
Vol 629 ◽  
pp. 105-109
Author(s):  
Yi Qiang He ◽  
Jian Ming Yang ◽  
Bin Qiao ◽  
Li Chao Feng
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Particle Volume ◽  
Sic Particles ◽  
The Matrix ◽  
Fraction Increase

SiCP/Cu composite was prepared by metal injection molding process. Microstructure, mechanical properties, fracture surface, and wear resistance of SiCP/Cu composite were investigated in this study. The research results show that SiCP/Cu were sintered sucessfully by the sintering process with hydrogen protection and high temperature of 1050°C. The tensile strength of the composites depends on the fraction and distribution of SiC particles which is resulted from microcracks nucleate in the matrix between SiC particles because of SiC particle aggregation. The tensile strengths of 5vol.%, 10vol.%, and15vol.%SiCP/Cu are 254MPa, 291MPa and 278MPa separately. SiC particles are contribute to enhance the abrasive resitance of the composite when particle volume fraction increase from 10% to 15%.

scholarly journals Strengthening of a Near β-Ti Alloy through β Grain Refinement and Stress-Induced α Precipitation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4255 ◽  
Author(s):  
Wei Chen ◽  
Chao Li ◽  
Kangtun Feng ◽  
Yongcheng Lin ◽  
Xiaoyong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Strength ◽  
Ti Alloy ◽  
Β Phase ◽  
Ti Alloys ◽  
Α Phase ◽  
Transmission Electron ◽  
Strength And Ductility ◽  
Α Particles

Near β-Ti alloys with high strength and good ductility are desirable for application in aviation and aerospace industries. Nevertheless, strength and ductility are usually mutually exclusive in structural materials. Here we report a new thermo-mechanical process, that is, the alloy was cross-rolled in β field then aged at 600 °C for 1 h. By such a process, a high strength (ultimate tensile strength: 1480 MPa) and acceptable ductility (elongation: 10%) can be simultaneously achieved in the near β-Ti alloy, based on the microscale β matrix and nanoscale α phase. The microstructure evolution, mechanical properties and strengthening mechanisms have been clarified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the grain size of the β phase progressively decreased with the increasing of rolling reduction. Moreover, dense dislocation structures and martensite phases distributed in the cross-rolled β matrix can effectively promote the precipitation of nanoscale α particles. TEM analyses confirmed that a heat-treatment twin was generated in the newly formed α lath during aging. These findings provide insights towards developing Ti alloys with optimized mechanical properties.

Microstructures and Mechanical Properties of a New Type of High Temperature Titanium Alloy

2020 ◽  
Vol 993 ◽  
pp. 208-216
Author(s):  
Ya Peng Cui ◽  
Zi Yong Chen ◽  
Xiao Zhao Ma ◽  
Ying Ying Liu ◽  
Zhi Lei Xiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
High Temperature ◽  
High Strength ◽  
Solution Temperature ◽  
Β Phase ◽  
Α Phase ◽  
Heat Treated ◽  
New Type ◽  
Microstructures And Mechanical Properties

The microstructures and mechanical properties of a new type near α high temperature titanium alloy Ti-6.5Al-2.5Sn-9Zr-0.5Mo-0.25Si-1Nb-1W-0.3Re (wt. %) (denoted as TA6.5) were investigated. It was observed that the microstructure of forged TA6.5 mainly consisted of deformed lamellar α phase, small amount of equiaxed α phase, and residual β phase, exhibiting high strength and comparatively low elongation. Three different heat treatments processes were performed on forged TA6.5. The results showed that all heat treated alloys displayed high tensile strengths, and the values of strength parameters were almost unchanged with the increasing solution temperature, ascribing to the combination effects of decreasing primary α phase and increasing contents and widths of secondary α phase and lamellas. The tensile elongations of heat treated alloys tested at 650 °C decreased slightly with the increasing solution temperature, which is due to the increased width of secondary α lamellas and the generation of coarse grain boundary α phase. TA6.5 treated in the process of 990 °C/1 h/AC+700 °C/4 h/AC exhibited excellent comprehensive mechanical properties, i.e. the ultimate tensile strength of 829 MPa, yield strength of 707 MPa and elongation of 18.73% respectively.

scholarly journals Affect of prolonged thermal exposure on microstructure and mechanical properties of ultrafine-grained bioinert Zr - 1 wt. % Nb and Ti - 45 wt. % Nb alloys

2020 ◽  
pp. 9-16
Author(s):  
A.Yu. Eroshenko ◽  
◽  
Yu.P. Sharkeev ◽  
M.A. Khimich ◽  
P.V. Uvarkin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Exposure ◽  
Annealing Duration ◽  
Structural Elements ◽  
Β Phase ◽  
Ω Phase ◽  
Α Phase ◽  
Microstructure And Mechanical Properties ◽  
Ultrafine Grained ◽  
The Matrix

The results for thermal stability of the microstructure and mechanical properties of ultrafine-grained alloys Zr-1 wt. % Nb and Ti-45 wt. % Nb alloys after long-term thermal annealing at temperature of 400°C are presented. It is shown that in the Zr-1 wt.%Nb alloy in the ultrafine-grained state, increase in the annealing duration from 5 to 360 hours leads to growth of the structural elements (grains, sub-grains, fragments) of the matrix phase a - Zr and the particles β-Nb. This fact is due to the processes of recrystallization. It leads to softening of the alloy and decrease of microhardness and yield stress. It was also found that annealing up to 360 hours does not affect the size of the structural elements of the matrix β-phase in the Ti-45 wt. % Nb alloy, but contributes to the noticeable growth of the α-phase and ω-phase grains. According to our results, softening of the Ti-45 wt. % Nb alloy and decrease in its mechanical characteristics are associated with the processes of return at the grain boundaries, as well as with growth of the nanoscale grains of α-phase and ω-phase and decrease in their contribution to dispersion hardening.

Study on the Mechanical Property and Microstructure of Surgical Implanted Ti-6Al-7Nb Titanium Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 945-949
Author(s):  
Jiang Bo Wang ◽  
Zai Yan Shang ◽  
Zhi Shan Yuan ◽  
Jin Zhou ◽  
Zhao Wei Feng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Hip Replacement ◽  
Electron Microscopic ◽  
Β Phase ◽  
Α Phase ◽  
Scanning Electron Microscopic ◽  
The Matrix ◽  
Orthopedic Applications ◽  
Stabilizing Element

Ti-6Al-7Nb titanium alloy is attractive to medical device industry for orthopedic applications, such as total hip replacement systems, fracture fixation plates, intermedullary rods and nails, spinal devices, screws, and wires. Substituting Niobium for Vanadium as the beta stabilizing element, Ti-6Al-7Nb titanium alloy shows higher biocompatability than Ti-6Al-4V titanium alloy. The present research is designed to investigate the influence of annealling temper on the mechanical properties and microstructures of Ti-6Al-7Nb titanium alloy, by optical microscopic (OM) and scanning electron microscopic (SEM), and tensile test. The results show that the microstructures after recrystalization heat treatment comprise a mount of equiaxed α grains in the matrix of equiaxed β phase with α (hcp)/ β (bcc) platelets. The microstructures with partial recrystalization α phase possess better mechanical properties which conform to the ASTM F 1295 standard and ISO 5832-11 standard. Compared with Ti-6Al-4V titanium alloy and CP titanium alloy, Ti-6Al-7Nb titanium alloy is suitable to be used as implanted biomaterial devices to replace ill-functioning or missing tissues or organs.

The Effect of Heat Treatment on Mechanical Properties of Car Interior Fabric Used for Injection Molding

2012 ◽  
Vol 532-533 ◽  
pp. 234-237
Author(s):  
Wei Lai Chen ◽  
Ding Hong Yi ◽  
Jian Fu Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Injection Molding ◽  
High Temperatures ◽  
Material Properties ◽  
Injection Molding Process ◽  
Molding Process ◽  
Composite Fabrics

The purpose of this paper is to study the effect of high temperature in injection molding process on mechanical properties of the warp-knitted and nonwoven composite fabrics (WNC)used in car interior. Tensile, tearing and peeling properties of WNC fabrics were tested after heat treatment under120, 140,160,180°C respectively. It was found that, after 140°C heat treatment, the breaking and tearing value of these WNC fabrics are lower than others. The results of this study show that this phenomenon is due to the material properties of fabrics. These high temperatures have no much effect on peeling properties of these WNC fabrics. It is concluded that in order to preserve the mechanical properties of these WNC fabrics, the temperature near 140°C should be avoided possibly during injection molding process.

Tribology study of hydroxyapatite (HAp) scaffold blended single based binder via rheology and mechanical properties

2017 ◽  
Vol 69 (3) ◽  
pp. 414-419
Author(s):  
Mimi Azlina Abu Bakar ◽  
Siti Norazlini Abd Aziz ◽  
Muhammad Hussain Ismail
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Palm Stearin ◽  
Polymeric Materials ◽  
High Energy ◽  
Single Step ◽  
Injection Molding Process ◽  
Plastic Behavior ◽  
Molding Process ◽  
Content Type

Purpose This paper aims to investigate the vital characteristic of an innovative ceramic injection molding (CIM) process for orthopedic application with controlled porosity and improved tribological and mechanical properties which were affected by complex tribological interactions, whether lubricated like hip implants and other artificial prostheses. The main objective is to maximize the usage of palm stearin as a single based binder as the function of flow properties during injection molding process. Design/methodology/approach The binder used in this present study consists of 100 per cent palm stearin manufactured by Kempas Oil Sdn Bhd and supplied by Vistec Technology Sdn Bhd. The feedstock was prepared by using a Z-blade mixer (Thermo Haake Rheomix OS) and Brabender mixer model R2400. The feedstock prepared was injection molded using a manually operated vertical benchtop machine with an average pressure of about 5-7 bars. The firing step included the temporary holds at intermediate temperatures to burn out organic binders. At this stage, the green molded specimen was de-bound using a single-step wick-debinding method. Findings The maximum content of ceramic material is applied to investigate the efficiencies of net formulation that can be achieved by ceramic materials. The longer the viscosity will change with shear rate, the higher the value of n obtained instead. From the slope of the curves obtained in Figure 3, the value of n for the feedstock was determined to be less than 1, which indicates a pseudoplastic behavior and suitability for the molding process. Moreover, high shear sensitivity is important in producing complex and intrinsic specimens which are leading products in the CIM industry. Originality/value The feedstock containing HAp powder and palm stearin binder was successfully prepared at very low temperature of 70°C, which promoting a required pseudo-plastic behavior during rheological test. The single binder palm stearin should be optimized in other research works carried out, as palm stearin is most preferred compared to other polymeric materials that provided high energy consumption when subjected to the sintering process. Besides the binder is widely available in Malaysia, low cost and harmless effect during debinding process.

Prediction of Elastic Modulus of Glass Short Fiber/Wood Powder/Polypropylene Hybrid Composites

2013 ◽  
Author(s):  
Ying Yu ◽  
Manabu Nomura ◽  
Hiroyuki Hamada
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Hybrid Composites ◽  
Length Distribution ◽  
Wood Particle ◽  
Short Fiber ◽  
Injection Molding Process ◽  
Orientation Factor ◽  
Wood Powder ◽  
Molding Process

Recent years, thermoplastics incorporated with particulate fillers have been gained high interests. To improve the mechanical properties of the natural particle reinforced polymer plastics, hybrid structure has been applied on the composite combining natural particle with stronger synthetic fibers. However, the reinforcing mechanism of the hybrid composite is quite complicated. Experiments on it may become time consuming and cost prohibitive. Therefore, researchers are interested in studying variable models to predict the elastic properties of the composites. In this study, glass short fiber/wood particle/pp hybrid composites were prepared by injection molding process at a fixed reinforcement to matrix ratio of 51:49. 4 kinds of hybrid specimens with glass fiber/wood particle ratios of 41:10, 31:20, 21:30 and 11:40 were fabricated. The effect of hybridization content on the mechanical properties of the composites was evaluated based on tensile test. Theoretically, the elastic modulus of hybrid composites was predicted by using the rule of hybrid mixtures (RoHM) equation and classical lamination theory (CLT) and the accuracy of the two estimation models has been discussed. Results showed that it can be considered the hybridization of wood powder into glass/PP composite could contribute to a similar high elastic modulus with high green degree. On the other hand, the fiber orientation factor, fiber length distribution factor, powder dispersion factor were very important factors and need to be considered in the prediction model.

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