scholarly journals FAST-forge of novel Ti-6Al-4V/Ti-6Al-2Sn-4Zr-2Mo bonded, near net shape forgings from surplus AM powder

2020 ◽  
Vol 321 ◽  
pp. 03010
Author(s):  
Oliver Levano ◽  
Nicholas Weston ◽  
Jacob Pope ◽  
Adam Tudball ◽  
David Lunn ◽  
...  

Titanium alloys are used extensively in the aerospace sector due to the good combination of high strength-to-weight ratio and corrosive resistance. Many aerospace components are exposed to extreme service stress states and temperatures, which in some applications could compromise the component’s performance if a single titanium alloy is used. A potential solution to this issue could be the combination of dissimilar titanium alloys in subcomponent regions, achieved through consolidating powders via field assisted sintering technology (FAST-DB) and subsequent hot forging (FAST-forge). In this paper, near net shape titanium-titanium alloy demonstrator components are produced from oversized AM powders in just two hybrid solid-state steps; FAST-DB and hot forging.

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 296 ◽  
Author(s):  
Nicholas S. Weston ◽  
Martin Jackson

Titanium alloys have excellent properties, but components are very expensive due to the high levels of processing required, such as vacuum melting, multi-stage forging, and machining. As a result, forged titanium alloy components are largely exclusive to the aerospace industry, where a high strength-to-weight ratio, corrosion resistance, and excellent fatigue resistance are essential. However, a typical buy-to-fly ratio for such components is approximately 9:1, as much of the forged billet is machined to swarf. The quantity of waste titanium alloy swarf generated is increasing as aircraft orders, and the titanium components contained within them, are increasing. In this paper, waste swarf material has been recycled using the two-step solid-state FAST-forge process, which utilizes field assisted sintering technology (FAST) followed by hot forging. Cleaned Ti-6Al-4V swarf was fully consolidated using the FAST process at sub-transus and super-transus temperatures, followed by hot forging at sub-transus temperatures at different strain rates. It was demonstrated that swarf-derived Ti-6Al-4V FAST billets have equivalent hot forging flow behaviour and resultant microstructures when directly compared to equivalently processed conventional expensive hydride–dehydride powder, and previously reported Kroll-derived melt-wrought material. This demonstrates that titanium swarf is a good quality feedstock for downstream processing. Additionally, FAST-forge is a viable processing route for the closed-loop recycling of machining waste for next-generation components in vehicles and non-aerospace applications, which is game changing for the economics of titanium alloy components.


2011 ◽  
Vol 264-265 ◽  
pp. 1281-1286 ◽  
Author(s):  
Leonardo Daniele Scintilla ◽  
Donato Sorgente ◽  
Luigi Tricarico

The high strength to weight ratio and good corrosion resistance of titanium alloys, have led to an increasing use of these materials, particularly in the aerospace industry. The laser cutting technique may be a promising tool in machining titanium alloy parts like those with subsequent welding requirement: in this case, surface quality of the kerf edges is of great importance. The low thermal conductivity and the high chemical activity of titanium alloys lead, in fact, to alterations of the surface properties of the machined zone. This paper presents the results of titanium alloy laser cutting using a 2 kW fiber laser. The cutting process was performed in continuous wave mode and using Argon as shear gas. Laser cuts were realized on titanium alloy Ti6Al4V sheets 1mm thick. Image analysis and microscopy, were carried out to examine the cutting edge quality features including thickness of the recast layer and heat-affected zone.


2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.


2016 ◽  
Vol 704 ◽  
pp. 75-84 ◽  
Author(s):  
Fei Yang ◽  
Brian Gabbitas ◽  
Ajit Pal Singh ◽  
Stella Raynova ◽  
Hui Yang Lu ◽  
...  

Blended Elemental Powder Metallurgy (BE-PM) is a very attractive method for producing titanium alloys, which can be near-net shape formed with compositional freedom. However, a minimization of oxygen pick-up during processing into manufactured parts is a big challenge for powder metallurgy of titanium alloys. In this paper, different approaches for preparing titanium alloy parts by powder compact extrusion with 0.05-0.1wt.% of oxygen pick-up during manufacturing are discussed. The starting materials were a powder mixture of HDH titanium powder, other elemental powders and a master alloy powder. Different titanium alloys and composites, such as Ti-6Al-4V, Ti-4Al-4Sn-4Mo-0.5Si, Ti-5Al-5V-5Mo-3Cr, and Ti-5Al-5V-5Mo-3Cr-5vol%TiB, with different profiles such as round and rectangular bars, a wedge profile, wire and tubes have been successfully manufactured on a laboratory and pilot-plant scale. Furthermore, a possible route for scaling up the titanium processing capabilities in the University of Waikato has also been discussed.


Author(s):  
Annayath Maqbool ◽  
Noor Zaman Khan ◽  
Arshad Noor Siddiquee

Abstract The use of lighter materials is one of the efficient means to mitigate the increasing demands on fuel resources, reduce CO2 emissions. Mg is one of the lightest material available and possesses exciting range of properties such as low density and high strength to weight ratio. Despite such exciting properties, the applications of Mg and its alloys were very limited in aerospace, automotive and biomedical industries but recently the application is picking-up. The restricted application is attributed to anisotropy, poor corrosive resistance and inflammability of Mg. The current review addresses the barriers limiting the widespread application of Mg based materials. Furthermore, the mitigation of the problems of anisotropy, poor corrosion resistance, ductility and inflammability of Mg are critically reviewed. The findings of this research provide insights of the processing techniques, properties and how to address the potential barriers of limited applications. The review paper will assist and motivate the researchers to ponder and overcome numerous problems related to Mg and its alloys by understanding the importance of each problem discussed in this review. An attempt has also been made to arrange research status on issues and the mitigation thereof with respect to Mg and its alloys as single reference point.


2021 ◽  
Vol 1016 ◽  
pp. 964-970
Author(s):  
Nageswara Rao ◽  
Geetha Manivasagam

Beta titanium alloys have several attractive features; this has resulted in this group of alloys receiving much attention since 1980’s. Among the attributes which distinguish them for their superiority over other structural materials are (i) high strength to which they can be heat treated, resulting in high strength to weight ratio (ii) high degree of hardenability which enables heat treatment in large section sizes to high strength levels (iii) excellent hot and cold workability, making them as competitive sheet materials etc. The standard heat treatment consists of solution treatment in beta or alpha plus beta phase field followed by aging. However, certain aging treatments can render the materials in a state of little or no ductility; the designer has to be aware of this behaviour and has to keep away from such treatments while working with the materials. Such unfavourable aging treatments may adversely affect not only the static properties such as reduction in area and elongation in a tensile test, but also dynamic properties such as impact toughness. Results of fractographic studies are in line with those of mechanical testing. The authors would present the foregoing analysis, based primarily on the wide-ranging researches they carried out on beta titanium alloy Ti15-3 and to some extent data published by researchers on other grades of beta titanium alloys. An attempt is made to explain the mechanisms underlying the embrittlement reactions that take place in beta titanium alloys under non-optimal aging treatments.


Lubricants ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 65 ◽  
Author(s):  
Kaur ◽  
Ghadirinejad ◽  
Oskouei

The need for metallic biomaterials will always remain high with their growing demand in joint replacement in the aging population. This creates need for the market and researchers to focus on the development and advancement of the biometals. Desirable characteristics such as excellent biocompatibility, high strength, comparable elastic modulus with bones, good corrosion resistance, and high wear resistance are the significant issues to address for medical implants, particularly load-bearing orthopedic implants. The widespread use of titanium alloys in biomedical implants create a big demand to identify and assess the behavior and performance of these alloys when used in the human body. Being the most commonly used metal alloy in the fabrication of medical implants, mainly because of its good biocompatibility and corrosion resistance together with its high strength to weight ratio, the tribological behavior of these alloys have always been an important subject for study. Titanium alloys with improved wear resistance will of course enhance the longevity of implants in the body. In this paper, tribological performance of titanium alloys (medical grades) is reviewed. Various methods of surface modifications employed for titanium alloys are also discussed in the context of wear behavior.


2013 ◽  
Vol 763 ◽  
pp. 29-49 ◽  
Author(s):  
A. Prabukarthi ◽  
V. Krishnaraj ◽  
M. Senthil Kumar

Titanium alloys present superior properties like resistance to corrosion, high strength to weight ratio etc, but possess poor machinability. Titanium alloy Ti-6Al-4V is the most commonly used titanium alloy in aerospace and medical device industries. Titanium and its alloys are notorious for their poor thermal properties and are classified as difficult-to-machine materials. Drilling is an important machining process since it is involved in nearly all titanium applications. It is desirable to develop optimized drilling processes for Ti and improve the hole characteristics such as hole diameter, circularity and exit burr of currently available processes. Due to the low machinability of the alloys under study, selecting the machining conditions and parameters is crucial. The range of spindle speed and feed rate, which provide a satisfactory tool life, is very limited. The hole quality (hole diameter and circularity), thrust force, torque and exit burr were evaluated at various spindle speeds, feed rates combinations. The optimized parameter is chosen using the multi-objective weighted sum optimization technique.


2011 ◽  
Vol 83 ◽  
pp. 191-196
Author(s):  
Justyna Rozwadowska ◽  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Takashi Honda ◽  
Hitonobu Koike ◽  
...  

The influence of gas nitriding of commercial pure titanium and Ti-6Al-4V (Ti64) alloy by using a Q-sw laser on the wear loss during rolling contact fatigue is investigated. Despite very good biocompatibility, high strength to weight ratio and corrosion resistance, the tribological properties of titanium alloys are inferior to those of other metal alloys, such as steel. Fretting and wear related aspects become important issues when titanium alloys are used in rolling contact applications. Titanium bearings are employed in applications requiring high strength, light weight, and minimum maintenance (for example, aerospace and defense industries). In this work, a Q-sw laser was used to coat pure commercial titanium and Ti-6Al-4V bearings with TiN in a closed chamber in nitrogen atmosphere. The samples were tested under water by using a thrust-type rolling contact fatigue machine. The microstructure, morphology and crystallographic texture of the layers were observed by laser confocal microscope, scanning electron microscope and electron backscatter diffraction (EBSD). By optimizing the laser processing parameters, such as laser scanning speed, power and beam diameter, thin TiN coats of 1 to 3 mm were produced. The wear loss of the coated samples was at least ten times lower than that of the uncoated bearings.


2005 ◽  
Vol 475-479 ◽  
pp. 563-568
Author(s):  
Yong Qing Zhao ◽  
Lian Zhou

China pays great attentions to the development of titanium alloys and their basic theory because of their excellent properties. New titanium alloys and their new basic theories developed in China in recent five years were reviewed, for example, high temperature Ti alloys, burn resistant titanium alloys, high strength and middle strength titanium alloys and so on. The developing directions in the next 5 to 10 years were forecast.


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