Mechanical Properties of Single-Melt PAM Processed Ti-6Al-4V Forgings

2013 ◽  
Vol 551 ◽  
pp. 186-209 ◽  
Author(s):  
Mustafa Guclu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Oxygen Content ◽  
Low Cost ◽  
Vacuum Arc ◽  
Fatigue And Fracture ◽  
Microstructure Examination ◽  
Toughness Testing ◽  
Alpha Beta ◽  
Effect Of Oxygen

Ti-6Al-4V pancakes were manufactured by alpha-beta forging using single-melt (SM) plasma arc melt (PAM) billet stock at three oxygen levels, 0.16, 0.20 and 0.24 wt%, along with a standard double vacuum arc remelted (2XVAR) billet stock at 0.17 wt% oxygen for baseline comparison. Mechanical properties of forgings in the mill-, recrystallization- and beta-annealed conditions were then characterized by microstructure examination, tensile, smooth bar axial fatigue and fracture toughness testing in radial orientation. The effect of oxygen content on mechanical properties of the forgings was assessed. All SM PAM forgings exhibited slightly higher tensile and fatigue strength compared to those of 2XVAR. The fracture toughness values decreased with increasing oxygen content. Microstructures of all forgings were similar to those of conventional alpha-beta forgings. The data presented in this paper can be useful to designers in their efforts to introduce low-cost SM PAM Ti-6Al-4V (Ti-6-4) alloy forgings into various U.S. defense applications.

Effect of Oxygen Content in Powders on Microstructure and Mechanical Properties of WC-FeAl Composites Fabricated by Vacuum Sintering Technique

2015 ◽  
Vol 1088 ◽  
pp. 115-119 ◽  
Author(s):  
Ryoichi Furushima ◽  
Kiyotaka Katou ◽  
Koji Shimojima ◽  
Hiroyuki Hosokawa ◽  
Akihiro Matsumoto
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Oxygen Content ◽  
Rupture Strength ◽  
Powder Preparation ◽  
Vacuum Sintering ◽  
Transverse Rupture Strength ◽  
Sintered Composite ◽  
Lower Oxygen ◽  
Effect Of Oxygen

WC-FeAl composites were fabricated by vacuum sintering technique from mixture of WC and FeAl powders containing various oxygen content. Mechanical properties such as hardness, fracture toughness and transverse rupture strength were influenced by the oxygen content in the powders. Control of the oxygen content was succeeded by changing the powder preparation process. Contrary to expectations, the reduction of oxygen content led to degrade the fracture toughness and transverse rupture strength of the composites. This result was attributed to the microstructural change in the sintered composite. The sintered composite of lower oxygen content exhibited WC grain growth or inhomogeneous microstructure, which can be the cause of degradation of those mechanical properties. It was concluded that the oxygen content was one of the key factors to influence the microstructure or mechanical properties of WC-FeAl composites.

Fracture Toughness Testing for Improving the Safety of Gas Pipelines

2016 ◽  
Vol 821 ◽  
pp. 464-470
Author(s):  
Ľubomír Gajdoš ◽  
Martin Šperl
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Mechanical Tests ◽  
Internal Stresses ◽  
Pipe Material ◽  
Cylindrical Wall ◽  
Fracture Toughness Testing ◽  
Toughness Testing ◽  
Thin Walled

For standard fracture mechanical tests flat specimens (principally CT or SENB) are required. When investigating fracture mechanical properties of thin – walled pipes this brings about a problem because it is necessary to straighten pipe bands. However, this operation causes internal stresses to be induced not only in the semi-product subjected to straightening but also in finished specimens. A question therefore arises to what extent are then the magnitudes of the fracture toughness determined representative for the actual cylindrical wall. To solve this problem fracture mechanics tests were caried out on flat (straightened) CT specimens as well as on curved CT specimens with the natural curvature. The R – curves as well as the resulting parameters of the fracture toughness, obtained for both types of CT specimens, were compared and it was concluded that the fracture toughness of the pipe material determined on straightened CT specimens was practically the same as that obtained on curved CT specimens.

Mechanical Properties of Tank Car Steels Retired From the Fleet

2009 ◽  
Author(s):  
Peter C. McKeighan ◽  
David Y. Jeong ◽  
Joseph W. Cardinal
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Material Characterization ◽  
Laboratory Testing ◽  
Structural Integrity ◽  
Hazardous Materials ◽  
High Rate ◽  
Test Program ◽  
Testing Program ◽  
Toughness Testing

As a consequence of recent accidents involving the release of hazardous materials (hazmat), the structural integrity and crashworthiness of railroad tank cars have come under scrutiny. Particular attention has been given to the older portion of the fleet that was built prior to steel normalization requirements instituted in 1989. This paper describes a laboratory testing program to examine the mechanical properties of steel samples obtained from tank cars that were retired from the fleet. The test program consisted of two parts: (1) material characterization comprised of chemical, tensile and Charpy V-notch (CVN) impact energy and (2) high-rate fracture toughness testing. In total, steel samples from 34 tank cars were received and tested. These 34 tank cars yielded 61 different pre-1989 TC128-B conditions (40 shell and 21 head samples), three tank cars yielded seven different post-1989 TC128-B conditions (four shell and three head samples), and six tank cars yielded other material (A212, A515, and A285 steel) conditions (six shell and five head samples). The vast majority of the TC128-B samples extracted from retired tank cars met current TC128-B material specifications. Elemental composition requirements were satisfied in 97 percent of the population whereas the required tensile properties were satisfied in 82 percent of the population. Interpretation of the high-rate fracture toughness tests required dividing the pre-1989 fleet into quartiles that depended on year of manufacture or age, and testing three tank cars per quartile. Considering the high-rate fracture toughness results at 0°F for the pre-1989 fleet, 100 percent of the oldest two quartiles, 58 percent of the second youngest quartile, and 83 percent of the youngest quartile exhibited adequate or better fracture toughness (defined as toughness greater than 50 ksi√in). High-rate fracture toughness at –50°F was adequate for 83 percent of two quartiles (the youngest and second oldest), but the other two quartiles exhibited lower toughness with only 33 (2nd youngest) to 50 percent (oldest) exhibiting adequate properties.

scholarly journals Influence of Oxygen on the Fatigue Behaviour of Ti-6Al-7Nb Alloy

2016 ◽  
Vol 704 ◽  
pp. 44-52 ◽  
Author(s):  
Alexandra Amherd Hidalgo ◽  
Thomas Ebel ◽  
Wolfgang Limberg ◽  
Florian Pyczak
Keyword(s):  
Mechanical Properties ◽  
Oxygen Content ◽  
Treatment Time ◽  
Light And Electron Microscopy ◽  
Tensile Tests ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Four Point Bending ◽  
Initiation And Propagation ◽  
Effect Of Oxygen

One of the challenges in PM Ti alloys is to control the impurities level. Oxygen affects the microstructure and the mechanical properties of titanium alloys. Ti-6Al-7Nb is a promising alloy to use in PM due to its outstanding biocompatibility and mechanical properties required for load bearing medical implants. In this work, the influence of the impurities content on the ductility, fatigue resistance and microstructure of Ti-6Al-7Nb alloy processed by metal injection moulding was examined. Tensile and fatigue specimens were manufactured using Ti-6Al-7Nb gas atomized powder. Depending on the thermal treatment time, various oxygen contents were introduced into the specimens. The resulting oxygen content was determined by melt extraction technique. Tensile tests and high cycle four-point bending fatigue tests at room temperature were performed. First studies about the effect of oxygen content on crack initiation and propagation were done by the observation of microstructures and fractured surfaces using light and electron microscopy (SEM).

Si3N4/BN Composite Ceramics with Nd2O3-Al2O3-Y2O3 Ternary Additives by Pressureless Sintering

2010 ◽  
Vol 434-435 ◽  
pp. 106-108
Author(s):  
Ping Liu ◽  
Yong Feng Li ◽  
Xiang Dong Wang ◽  
Hai Yun Jin ◽  
Guan Jun Qiao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Flexural Strength ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Composite Ceramics ◽  
Fracture Toughness Testing ◽  
Β Phase ◽  
Toughness Testing

Si3N4/BN composite ceramics with 25vol% h-BN were prepared by pressure-less sintering process with Nd2O3/Al2O3/Y2O3 as sintering additives. The effects of these ternary additives on the densification behaviors and mechanical properties were investigated. XRD and FESEM were used to investigate the α-β phase transformation and microstructure. The XRD results showed that α-Si3N4 has transformed to β-Si3N4 completely in all the samples during the pressureless sintering process. The line shrinkage increased with the Nd2O3 contents increasing, and the highest line shrinkage (7.75%) was observed when 4wt% Nd2O3 was added, then decreased. The same trends were observed in flexural strength and fracture toughness testing. The ternary additives of Y2O3-Al2O3-Nd2O3 could improve the density, strength and fracture toughness of the material effectively.

Mechanical Properties of Toughened Polyester Reinforced with Untreated and Treated Kenaf Hybird Carbon Composite

2017 ◽  
Vol 894 ◽  
pp. 17-20
Author(s):  
Noor Najmi Bonnia ◽  
Aein Afina Redzuan ◽  
Siti Norasmah Surip ◽  
Noor Azlina Hassan
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Carbon Black ◽  
Hybrid Composites ◽  
Carbon Composite ◽  
Compression Moulding ◽  
Fracture Toughness Testing ◽  
Rubber Toughened ◽  
Toughness Testing

This research focusing on mechanical properties of rubber toughened polyester filled carbon black (RPCB) reinforced with untreated kenaf (RPCBUK) and treated kenaf (RPCBTK). The samples were fabricated via compression moulding technique in which 3 % of LNR was added as toughening agent in this composite. Percentages of carbon black (CB) is 4 % and kenaf used vary from 5,10,15,20 and 25wt %. The mechanical properties were evaluated by impact and fracture toughness testing. The result for each test was discussed to determine the most optimum loading of kenaf fibre used to produce the best properties of composite. Untreated hybrid composite showed improvement on impact strength as compared to RPCB composite. RPCBTK with 25% of kenaf and RPCBUK with 5% of kenaf loading give the highest impact strength among the hybrid composites, approaching the strength of neat polyester. Same trend shows by fracture toughness testing. The microstructures of the composites’ fracture surface images from scanning electron microscope (SEM) prove the mechanical properties of the hybrid composites.

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