Microstructures of LENS™ Deposited Nb-Si Alloys

2004 ◽  
Vol 842 ◽  
Author(s):  
Ryan R. Dehoff ◽  
Peter M. Sarosi ◽  
Peter C. Collins ◽  
Hamish L. Fraser ◽  
Michael J. Mills
Keyword(s):  
Elevated Temperatures ◽  
Alloy System ◽  
Enthalpy Of Mixing ◽  
Processing Parameters ◽  
Metal Loss ◽  
Matrix Composites ◽  
Heat Treated ◽  
Shaping Process ◽  
Structural Applications ◽  
Net Shaping

ABSTRACTNb-Si “in-situ” metal matrix composites consist of Nb3Si and Nb5Si3 intermetallic phases in a body centered cubic Nb solid solution, and show promising potential for elevated temperature structural applications. Cr and Ti have been shown to increase the oxidation resistance and metal loss rate at elevated temperatures compared to the binary Nb-Si system. In this study, the LENS™ (Laser Engineered Net Shaping) process is being implemented to construct the Nb-Ti-Cr-Si alloy system from elemental powder blends. Fast cooling rates associated with LENS™ processing yield a reduction in microstructural scale over conventional alloy processes such as directional solidification. Other advantages of LENS™ processing include the ability to produce near net shaped components with graded compositions as well as a more uniform microstructure resulting from the negative enthalpy of mixing associated with the silicide phases. Processing parameters can also be varied, resulting in distinct microstructural differences. Deposits were made with varying compositions of Nb, Ti, Cr and Si. The as-deposited as well as heat treated microstructures were examined using SEM and TEM techniques. The influence of composition and subsequent heat treatment on microstructure will be discussed.

Microstructural Evaluation of LENS™ Deposited Nb-Ti-Si-Cr Alloys

2002 ◽  
Vol 753 ◽  
Author(s):  
Ryan R. Dehoff ◽  
Peter M. Sarosi ◽  
Peter C. Collins ◽  
Hamish L. Fraser ◽  
Michael J. Mills
Keyword(s):  
Alloy System ◽  
Enthalpy Of Mixing ◽  
Ceramic Composites ◽  
Tem Analysis ◽  
Laser Engineered Net Shaping ◽  
Shaping Process ◽  
Structural Applications ◽  
Microstructural Evaluation ◽  
Net Shaping

ABSTRACTNb-Ti-Si “in-situ” metal ceramic composites consist of Nb3Si and Nb5Si3 intermetallic phases in a body centered cubic Nb solid solution, and show promising potential for elevated temperature structural applications. The addition of Cr has also been shown to increase the oxidation resistance at high temperatures. In this study, the LENS™ (Laser Engineered Net Shaping) process is being implemented to construct the Nb-Ti-Cr alloy system from elemental powder blends. Advantages of the LENS™ process include the ability to produce near net shaped components with graded compositions as well as a more uniform microstructure resulting from the negative enthalpy of mixing associated with the silicide phases. This study focuses on characterization of the microstructure of the Nb-27Ti-5Si-10Cr (at%) system using SEM and TEM analysis.

The Mg-Al-Ca Alloy System for Structural Applications at Elevated Temperatures

2007 ◽  
Author(s):  
Akane Suzuki ◽  
Nicholas D. Saddock ◽  
Jessica R. TerBush ◽  
J. Wayne Jones ◽  
Tresa M. Pollock ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Alloy System ◽  
Structural Applications

Heat treatment T4 and T6 effects on the tribological properties of sillimanite mineral-reinforced LM30 aluminium alloy composites at elevated temperatures

2021 ◽  
pp. 135065012110365
Author(s):  
Sandeep Sharma ◽  
Tarun Nanda ◽  
OM Prakash Pandey
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
Coefficient Of Friction ◽  
Elevated Temperatures ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Heat Treated ◽  
Wear And Friction ◽  
Grey Cast

The present study investigates effect of heat treatment on wear and friction behaviour of sillimanite/LM30 aluminium matrix composites at elevated temperatures (50–300 °C). The composites were prepared using a stir-casting process. Composites were reinforced with 3–15 wt.% sillimanite particle sizes of fine (1–20 μm):coarse (75–106 μm) in the ratio of 1:3, 1:1 and 3:1, respectively. Next, the composites were subjected to T4 and T6 heat treatment. For T4 heat treatment, composites were heated at 550 °C for 1 h, water quenched and naturally aged (at room temperature) for 480 h. Further, for T6 heat treatment composites were artificially aged at 200 °C for 4 h and air cooled. Hardness of composites improved with increase in particle weight percentage and increases in the ratio of fine particles in the mix. Maximum improvement in hardness was observed for 15 wt.% T6 heat-treated composites with fine:coarse in the ratio of 3:1. The addition of sillimanite particles improved wear resistance and coefficient of friction of the composites. Wear and friction analysis revealed that beyond 200 °C, wear behaviour of composites changed from mild to severe. Further, the heat treatment of composites improved wear resistance and coefficient of friction. Wear rate and friction coefficient of T6 heat-treated 15 wt.% composite with fine:coarse as 3:1 at 200 °C decreased by 70% and 52%, respectively. X-ray diffraction of wear tracks and wear debris of T6 heat-treated composites revealed the formation of intermetallics and oxides on the wornout surface of the composites. Scanning electron microscopy analysis of wear tracks and debris revealed that at elevated temperatures, abrasive and adhesive wear was dominant for the material removal mechanism. The developed composites exhibited nearly wear behaviour similar to that of grey cast iron used in brake rotors. Thus, sillimanite/LM30 aluminium matrix composites provide a suitable substitute to replace heavy grey cast iron components used in automobile industry.

On the Plastic Flow Behavior of Ti-6Al-4V Alloy during Multi-Stand Tandem Hot Rolling

2010 ◽  
Vol 638-642 ◽  
pp. 407-412
Author(s):  
Li Qing Chen ◽  
Shuang Liang ◽  
Xiang Hua Liu
Keyword(s):  
Plastic Flow ◽  
Hot Rolling ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Rolling Process ◽  
Processing Parameters ◽  
Phase Region ◽  
Two Phase ◽  
Heat Treated ◽  
Structural Parts

Titanium alloys are usually used as structural parts in forged and subsequent heat treated state. Up to now, there have been rare researches appeared on their shaping or forming by multi-stand tandem hot rolling. In this article, we choose Ti-6Al-4V as experimental material and a simulated research has been carried out in a thermo-mechanical simulator MMS-300 to model its hot-rolling process. The plastic flow behavior for Ti-6Al-4V alloy during hot-working has been determined at various deformation temperatures and deformation rates by considering its hot-rolling in single or two phase region. The deformation mechanisms at elevated temperatures are also analyzed in correlation with its deformation activation energy. This research can provide guidance in designing processing parameters for hot-rolling of Ti-6Al-4V alloy.

Pore Formation in Laser-Assisted Powder Deposition Process

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
L. Wang ◽  
P. Pratt ◽  
S. D. Felicelli ◽  
H. El Kadiri ◽  
J. T. Berry ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Process Parameters ◽  
Pore Formation ◽  
Volume Fraction ◽  
Deposition Process ◽  
Processing Parameters ◽  
Shaping Process ◽  
Steel Aisi ◽  
X Ray Computed ◽  
Net Shaping

Pore formation remains a concern in the area of rapid manufacturing by the laser engineered net shaping process. Results usually conflict on the origin of these pores; whether it should stem from an effect due to the physical/mechanical properties of the material or from an effect purely related to the processing parameters. We investigated this problem spanning a range of process parameters for deposition and using three different material powders, namely, an AISI 410 grade stainless steel, AISI 316L grade stainless steel, and AISI 4140 grade medium-carbon low alloy steel. The volume fraction, number density, and size distribution of pores were quantified using X-ray computed tomography and optical microscopy. Pores formed both at the interface between the adjacent layers and within the bulk of the layer. They were systematically sensitive to both the powder material composition and the process parameters.

Ta and Nb Reinforced MoSi2

1990 ◽  
Vol 194 ◽  
Author(s):  
David H. Carter ◽  
Patrick L. Martin
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Crack Propagation ◽  
Elevated Temperatures ◽  
Hot Working ◽  
Matrix Composites ◽  
Ductile Phase ◽  
Structural Applications

AbstractMoSi2 matrix composites have been recognized lately as potential materials for structural applications at elevated temperatures. Specifically, MoSi2 composites may exhibit useful properties at temperatures to 1400°C. Previous work improved the yield strength of MoSi2 at 1400°C by a factor of five through SiC whisker reinforcement. Current research is directed towards increasing the fracture toughness of MoSi2 through the addition of ductile phase reinforcements such as niobium and tantalum. The reaction between Nb and MoSi2 to form (Mo,Nb)5 Si3 proceeds with faster kinetics at hot isostatic press temperatures as low as 1100°C when compared to the reaction between Ta and MoSi2 to form (Mo,Ta)5Si3. This reaction product exhibits very poor properties, as evidenced by crack propagation through this layer during fracture. The feasibility of hot working these composites to produce tailored microstructures is examined.

scholarly journals Synthesis of Ti-Al-xNb Ternary Alloys via Laser-Engineered Net Shaping for Biomedical Application: Densification, Electrochemical and Mechanical Properties Studies

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 544
Author(s):  
Lehlogonolo Rudolf Kanyane ◽  
Abimbola Patricia Idowu Popoola ◽  
Sisa Pityana ◽  
Monnamme Tlotleng
Keyword(s):  
Biomedical Application ◽  
Corrosion Behaviour ◽  
Alloy System ◽  
Processing Parameters ◽  
Ternary Alloys ◽  
Al Alloy ◽  
Heart Transplants ◽  
Medical Interventions ◽  
Net Shaping ◽  
The Cost

The lives of many people around the world are impaired and shortened mostly by cardiovascular diseases (CVD). Despite the fact that medical interventions and surgical heart transplants may improve the lives of patients suffering from cardiovascular disease, the cost of treatments and securing a perfect donor are aspects that compel patients to consider cheaper and less invasive therapies. The use of synthetic biomaterials such as titanium-based implants are an alternative for cardiac repair and regeneration. In this work, an in situ development of Ti-Al-xNb alloys were synthesized via laser additive manufacturing for biomedical application. The effect of Nb composition on Ti-Al was investigated. The microstructural evolution was characterized using a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). A potentiodynamic polarization technique was utilized to investigate the corrosion behavior of TiAl-Nb in 3.5% NaCl. The microhardness and corrosion behaviour of the synthesized Ti-Al-Nb alloys were found to be dependent on laser-processing parameters. The microhardness performance of the samples increased with an increase in the Nb feed rate to the Ti-Al alloy system. Maximum microhardness of 699.8 HVN was evident at 0.061 g/min while at 0.041 g/min the microhardness was 515.8 HVN at Nb gas carrier of 1L/min, respectively.

ChemInform Abstract: The Mg-Al-Ca Alloy System for Structural Applications at Elevated Temperatures

ChemInform ◽  
2008 ◽  
Vol 39 (12) ◽  
Author(s):  
Akane Suzuki ◽  
Nicholas D. Saddock ◽  
Jessica R. TerBush ◽  
J. Wayne Jones ◽  
Tresa M. Pollock ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Alloy System ◽  
Structural Applications

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

FEDERATED F401.5Ni

Alloy Digest ◽  
1974 ◽  
Vol 23 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Aluminum Casting ◽  
Aluminum Casting Alloy ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition

Abstract FEDERATED F401.5Ni is a heat-treatable aluminum casting alloy with high strength and good wear resistance in the fully heat-treated condition. It is recommended for castings requiring good strength at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-212. Producer or source: Federated Metals Corporation, ASARCO Inc..

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