scholarly journals Additive Manufacturing of Ti-Based Intermetallic Alloys: A Review and Conceptualization of a Next-Generation Machine

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4317
Author(s):  
Thywill Cephas Dzogbewu ◽  
Willie Bouwer du Preez
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Complex Geometries ◽  
Intermetallic Alloys ◽  
Tial Alloys ◽  
Conventional Methods ◽  
Manufacturing Technologies ◽  
In Situ Heat Treatment

TiAl-based intermetallic alloys have come to the fore as the preferred alloys for high-temperature applications. Conventional methods (casting, forging, sheet forming, extrusion, etc.) have been applied to produce TiAl intermetallic alloys. However, the inherent limitations of conventional methods do not permit the production of the TiAl alloys with intricate geometries. Additive manufacturing technologies such as electron beam melting (EBM) and laser powder bed fusion (LPBF), were used to produce TiAl alloys with complex geometries. EBM technology can produce crack-free TiAl components but lacks geometrical accuracy. LPBF technology has great geometrical precision that could be used to produce TiAl alloys with tailored complex geometries, but cannot produce crack-free TiAl components. To satisfy the current industrial requirement of producing crack-free TiAl alloys with tailored geometries, the paper proposes a new heating model for the LPBF manufacturing process. The model could maintain even temperature between the solidified and subsequent layers, reducing temperature gradients (residual stress), which could eliminate crack formation. The new conceptualized model also opens a window for in situ heat treatment of the built samples to obtain the desired TiAl (γ-phase) and Ti3Al (α2-phase) intermetallic phases for high-temperature operations. In situ heat treatment would also improve the homogeneity of the microstructure of LPBF manufactured samples.

scholarly journals Effect of Post Processing Heat Treatment Routes on Microstructure and Mechanical Property Evolution of Haynes 282 Ni-Based Superalloy Fabricated with Selective Laser Melting (SLM)

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 629
Author(s):  
Anagh Deshpande ◽  
Subrata Deb Nath ◽  
Sundar Atre ◽  
Keng Hsu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
High Temperature ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Step Heat Treatment ◽  
Microstructure And Mechanical Property ◽  
In Situ Heat Treatment

Selective laser melting (SLM) is one of the most widely used additive manufacturing technologies. Fabricating nickel-based superalloys with SLM has garnered significant interest from the industry and the research community alike due to the excellent high temperature properties and thermal stability exhibited by the alloys. Haynes-282 alloy, a γ′-phase strengthened Ni-based superalloy, has shown good high temperature mechanical properties comparable to alloys like R-41, Waspaloy, and 263 alloy but with better fabricability. A study and comparison of the effect of different heat-treatment routes on microstructure and mechanical property evolution of Haynes-282 fabricated with SLM is lacking in the literature. Hence, in this manuscript, a thorough investigation of microstructure and mechanical properties after a three-step heat treatment and hot isostatic pressing (HIP) has been conducted. In-situ heat-treatment experiments were conducted in a transmission electron microscopy (TEM) to study γ′ precipitate evolution. γ′ precipitation was found to start at 950 °C during in-situ heat-treatment. Insights from the in-situ heat-treatment were used to decide the aging heat-treatment for the alloy. The three-step heat-treatment was found to increase yield strength (YS) and ultimate tensile strength (UTS). HIP process enabled γ′ precipitation and recrystallization of grains of the as-printed samples in one single step.

Microstructure and Mechanical Properties of TiB2/ Al-Si Composites Fabricated by TIG Wire and Arc Additive Manufacturing

2019 ◽  
Vol 944 ◽  
pp. 64-72
Author(s):  
Qing Feng Yang ◽  
Cun Juan Xia ◽  
Ya Qi Deng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
Filler Wire ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Bulky sample was made by using TIG wire and arc additive manufacturing (WAAM) technology, in which Ф1.6 mm filler wire of in-situ TiB2/Al-Si composites was selected as deposition metal, following by T6 heat treatment. The microstructure and mechanical properties of the bulky sample before and after heat treatment were analyzed. Experimental results showed that the texture of the original samples parallel to the weld direction and perpendicular to the weld direction was similar consisting of columnar dendrites and equiaxed crystals. After T6 heat treatment, the hardness of the sample was increased to 115.85 HV from 62.83 HV, the yield strength of the sample was 273.33 MPa, the average tensile strength was 347.33 MPa, and the average elongation after fracture was 7.96%. Although pore defects existed in the fracture, yet the fracture of the sample was ductile fracture.

scholarly journals Additive manufacturing of TiAl-based alloys

2020 ◽  
Vol 7 ◽  
pp. 35 ◽  
Author(s):  
Thywill Cephas Dzogbewu
Keyword(s):  
Additive Manufacturing ◽  
Elevated Temperatures ◽  
High Rate ◽  
Widespread Application ◽  
Tial Alloys ◽  
Powder Bed ◽  
Geometrical Accuracy ◽  
Heating And Cooling ◽  
Conventional Methods ◽  
Increasing Demand

The ever-increasing demand for developing lightweight, high-temperature materials that can operate at elevated temperatures is still a subject of worldwide research and TiAl-based alloys have come to the fore. The conventional methods of manufacturing have been used successfully to manufacture the TiAl-based alloy. However, due to the inherent limitations of the conventional methods to produce large TiAl components with intricate near-net shapes has limit the widespread application and efficiency of the TiAl components produced using conventional methods. Metal additive manufacturing such as Electron Beam Melting technology could manufacture the TiAl alloys with intricate shapes but lack geometrical accuracy. Laser powder bed fusion (LPBF) technology could manufacture the TiAl-based alloys with intricate shapes with geometrical accuracy. However, the inherent high rate of heating and cooling mechanisms of the LPBF process failed to produce crack-free TiAl components. Various preheating techniques have been experimented, to reduce the high thermal gradient and residual stress during the LPBF process that causes the cracking of the TiAl components. Although these techniques have not reached industrial readiness up to now, encouraging results have been achieved.

Effect of heat treatment and heat treatment in combination with lignosulfonate on in situ rumen degradability of canola cake crude protein, lysine, and methionine

2020 ◽  
Vol 100 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Piotr Micek ◽  
Katarzyna Słota ◽  
Paweł Górka
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Crude Protein ◽  
Dry Matter ◽  
Increased Temperature ◽  
Heat Treated ◽  
Cold Pressed ◽  
Temperature Heating ◽  
High Temperature Heating

The aim of this study was to determine the effect of heat treatment alone or in combination with the addition of lignosulfonate (LSO3) on canola cake protein, lysine, and methionine degradation in the rumen. Cold-pressed canola cake was left untreated, heated at 90, 110, 130, or 150 °C, or processed with 5% of LSO3 (in dry matter) and then heated. Effective rumen degradability of crude protein (CP), lysine, and methionine was less for treated than untreated canola cake (P < 0.05) and decreased with increased temperature of heating, but particularly when canola cake was heated at 150 °C (quadratic, P < 0.01). In general, effective rumen degradability of CP, lysine, and methionine was less for canola cake heated at 130 °C in combination with LSO3 compared with canola cake heat treated only (quadratic × LSO3 interaction, P ≤ 0.07). Results of this study indicate that high temperature heating (130 °C or greater for 60 min) may be necessary to protect canola cake protein from degradation in the rumen, and the combination of heat treatment and LSO3 may be more effective in protecting canola cake protein, lysine, and methionine from degradation in the rumen than the use of heat treatment only.

Innovative approaches to designing and manufacturing a prosthetic thumb

2020 ◽  
pp. 030936462094971 ◽  
Author(s):  
Branko Štefanovič ◽  
Monika Michalíková ◽  
Lucia Bednarčíková ◽  
Marianna Trebuňová ◽  
Jozef Živčák
Keyword(s):  
Additive Manufacturing ◽  
3D Scanning ◽  
Metacarpal Bone ◽  
Point Of View ◽  
Dominant Hand ◽  
Fused Filament Fabrication ◽  
Conventional Methods ◽  
Manufacturing Technologies ◽  
The Right ◽  
Manufacturing Time

Case description: Conventional methods for producing custom prosthetic fingers are time-consuming, can be uncomfortable for the patient, and require a skilled prosthetist. The subject was a 40-year-old male with congenital absence of the thumb and related metacarpal bone on the right non-dominant hand, anomaly of the lengths of individual upper limb segments, and contracture of the elbow joint. This hand presentation made it impossible for him to perform thumb opposition, which is a very important function for common daily activities. Objective: The goal was to design an individual passive thumb prosthesis using free open-source software, 3D scanning technology, and additive manufacturing methods (i.e., fused filament fabrication). Study design: Case report. Treatment: Artificial thumb prostheses with two types of bases and fastening interfaces were designed and manufactured. One combination was chosen as the best alternative. Outcomes: The shape, positioning, firmness, and fastening of the prosthesis were compliant enough for the patient to be able to hold objects with his healthy fingers and artificial thumb. This innovative approach to fabrication of a custom thumb prosthesis provided considerable advantages in terms of custom sizing, manufacturing time, rapid production, iteration, comfort, and costs when compared to conventional methods of manufacturing a hand prosthesis. Conclusion: The methodology of designing and manufacturing a prosthetic thumb using 3D scanning and additive manufacturing technologies have been demonstrated to be adequate from a practical point of view. These technologies show potential for use in the practice of prosthetics.

Jewelry Fabrication via Selective Laser Melting of Glass

2014 ◽  
Author(s):  
Miranda Fateri ◽  
Andreas Gebhardt
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Glass Powder ◽  
Fabrication Process ◽  
Complex Geometries ◽  
Laser Melting ◽  
Conventional Methods

Selective Laser Melting (SLM) is one of the Additive Manufacturing (AM) technologies applicable for producing complex geometries which are typically expensive or difficult to fabricate using conventional methods. This process has been extensively investigated experimentally for various metals and the fabrication process parameters have been established for different applications; however, fabricating 3D glass objects using SLM technology has remained a challenge so far although it could have many applications. This paper presents a summery on various experimental evaluations of a material database incorporating the build parameters of glass powder using the SLM process for jewelry applications.

High Temperature Microstructural Stability of Si3N4 in TiAl Alloys

2007 ◽  
Vol 534-536 ◽  
pp. 1577-1580
Author(s):  
Jee Hoon Choi ◽  
Dong Bok Lee
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Reaction Layer ◽  
Microstructural Stability ◽  
Tial Alloys ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma

Alloys of Ti-50 at.% Al with (3 and 10)wt.% Si3N4 particles were prepared by a mechanical alloying-spark plasma sintering (MA-SPS) method. The matrix consisted primarily of TiAl, Ti2AlN, TiN. Si3N4 was unstable in the matrix and started to decompose forming a Ti5Si3 reaction layer on the surface of former Si3N4 particles during sintering and heat treatment at 1373 K.

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