Wear Behavior of SHS Intermetallic Matrix Composites

1994 ◽  
Vol 350 ◽  
Author(s):  
J. A. Hawk ◽  
D. E. Alman
Keyword(s):  
Wear Resistance ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Matrix Composites ◽  
Temperature Synthesis ◽  
Intermetallic Matrix ◽  
High Temperature Synthesis ◽  
Abrasive Wear Behavior ◽  
Intermetallic Matrix Composites

AbstractA number of discontinuously reinforced, intermetallic matrix composites (i.e., TiAl/TiC, TiAl/TiB2, TiAl/Ti5Si3) were formed in situ through self-propagating, high-temperature synthesis (SHS) between elemental powders. This Bureau of Mines study characterizes the abrasive wear behavior of these composites. Wear behavior is discussed with respect to process history, and type and volume fraction of reinforcement. Generally, higher process temperatures lead to dense composites, resulting in better wear resistance. The wear behavior of the SHS intermetallic composites is compared to other intermetallics, produced by conventional techniques.

Microstructure of intermetallic-matrix composites produced in situ by self-propagating high-temperature synthesis

1994 ◽  
Vol 52 ◽  
pp. 708-709
Author(s):  
C. P. Doğan ◽  
D. E. Alman
Keyword(s):  
High Temperature ◽  
Exothermic Reaction ◽  
Ceramic Composites ◽  
Matrix Composites ◽  
Temperature Synthesis ◽  
Intermetallic Matrix ◽  
High Temperature Synthesis ◽  
Wide Range ◽  
Intermetallic Matrix Composites

Self-propagating, high-temperature synthesis (SHS) is one method of material production in which elemental constituents are ignited, initiating a self-sustaining, exothermic reaction that results in their transformation into intermetallic and ceramic compounds. In addition, several reactions can be initiated within a single body to form intermetallic-intermetallic, intermetallic-ceramic, or ceramic-ceramic composites in situ. The driving force for the reactions is the negative heats of mixing of the forming compounds, which results in the liberation of heat. The obvious advantages of SHS processing are that it presents an opportunity to produce near net-shape advanced materials and composites with a high level of purity in a relatively low-cost and energy efficient manner.At the U.S. Bureau of Mines, we are actively involved in the SHS processing of a wide range of singlephase intermetallic and intermetallic-matrix composites: TiAl, TiAl+TiB2, TiAl+TiC, TiAl+Ti5Si3, MoSi2+SiC. One key element of our study is a thorough understanding of the effect of processing variables, such as composition, temperature, pressure, time, powder morphology, etc., on the microstructure, and hence the properties, of these materials.

The Formation Process of the Microstructure of Al2O3-Al3Ti-Al In-Situ Composite

1997 ◽  
Vol 3 (S2) ◽  
pp. 727-728
Author(s):  
H.H. Luo ◽  
D.Z. Wang ◽  
H.X. Peng ◽  
Cheng Liu ◽  
C.K. Yao
Keyword(s):  
Squeeze Casting ◽  
Volume Fraction ◽  
Average Diameter ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Al Composite ◽  
Heat Treated ◽  
Intermetallic Matrix Composites ◽  
Processing Techniques

In the last decade, new in-situ processing techniques, such as DIMOX™, XD™, VLS and SHS, for fabricating metal and intermetallic matrix composites have emerged. It is expected that the in-situ formed composites may reveal not only excellent dispersion of fine reinforcing particles, but high thermodynamical stability and high temperature performance. The fully dense Al2O3-Al3Ti-57Vol%Al composite was in-situ processed by combing combustion synthesis with squeeze casting utilizing the reaction between TiO2 powder (with average diameter of 0.6μm and volume fraction of 14%) and pure Al (99.5%). First, the 14Vol%TiO2/Al bulk materials were fabricated via squeeze casting method, subsequently, the TiO2/Al materials were heat treated to form final in-situ composites. Using XRD, SEM, TEM and HRTEM techniques, the microstructure and its evolution were investigated.The X-ray diffraction pattern of the composite is shown in Fig.1 which indicates that the composite is composed of A12O3, Al3Ti and Al. According to the reaction formula between TiO2 and Al the volume fraction of Al in the composite is about 57%. Fig.2 is a typical scanning electron micrograph of the composite.

scholarly journals Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering

2018 ◽  
Vol 16 (1) ◽  
pp. 869-875
Author(s):  
Mediha İpek ◽  
Tuba Yener ◽  
Gözde Ç. Efe ◽  
Ibrahim Altınsoy ◽  
Cuma Bindal ◽  
...  
Keyword(s):  
High Hardness ◽  
Processing Technique ◽  
Metallic Phase ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
One Step ◽  
Intermetallic Matrix Composites ◽  
Hardness Values ◽  
A Current

AbstractIntermetallics are known as a group of materials that draws attention with their features such as ordered structure, high temperature resistance, high hardness and low density. In this paper, it is aimed to obtain intermetallic matrix composites and also to maintain some ductile Nb and Ti metallic phase by using 99.5% purity, 35-44 μm particle size titanium, niobium and aluminium powders in one step via recently developed powder metallurgy processing technique - Electric current activated/assisted sintering system (ECAS). In this way, metallic reinforced intermetallic matrix composites were produced. Dominant phases of TiAl3 and NbAl3 which were the first compounds formed between peritectic reaction of solid titanium, niobium and molten aluminum in Ti-Al-Nb system during 10, 30 and 90 s for 2000 A current and 1.5-2.0 voltage were detected by XRD and SEM-EDS analysis. Hardness values of the test samples were measured by Vickers indentation technique and it was detected that the hardnesses of intermetallic phases as 411 HVN whereas ductile metallic phase as 120 HVN.

Microstruciture and Properties of Intermetallic Matrix Composites Produced by Reaction Synthesis

1994 ◽  
Vol 350 ◽  
Author(s):  
D. E. Alman ◽  
J. A. Hawk ◽  
C. P. Dogan ◽  
M. Ziomek-Moroz ◽  
A. V. Petty
Keyword(s):  
Alkaline Solutions ◽  
Reaction Synthesis ◽  
Matrix Composites ◽  
Reaction Products ◽  
Hot Press ◽  
Press Temperature ◽  
Intermetallic Matrix ◽  
Microstructural Evaluation ◽  
Intermetallic Matrix Composites

AbstractIn this US Bureau of Mines study, a variety of TiAl based composites were produced in situ by reaction synthesis. Mixtures of elemental Ti, Al and B and Ti, Al, and Si powders were reactive hot-pressed to form TiAl reinforced with 10, 20, 25 or 60 vol. pct. TiB2 or Ti5Si3. Microstructural evaluation of the resultant composites confirmed that the reaction products were primarily TiAl and TiB2 or Ti5S3, with a small amount of Ti3Al. The hot-press temperature and pressure had a significant effect on the density of the composites. In general, higher temperatures and initiating the reaction under pressure promoted dense composites. Room temperature biaxial flexure strength tests indicated that the addition of the reinforcing phases can improve the strength of TiAl. Potentiodynamic experiments revealed that TiAl, TiAl+TiB2 and TiAl+Ti5Si3 composites display active-passive corrosion behavior in both acidic and alkaline solutions.

Volume Fraction Dependent Wear Behavior of Titanium-Reinforced Aluminum Matrix Composites Manufactured by Melt Infiltration Casting

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Ridvan Gecu ◽  
Ahmet Karaaslan
Keyword(s):  
Wear Resistance ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Pure Titanium ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Melt Infiltration ◽  
Cp Ti ◽  
Melt Infiltration Casting

This study aims to investigate the effect of volume fraction of commercially pure titanium (CP-Ti) on microstructural, mechanical, and tribological features of A356 aluminum matrix composites. Vacuum-assisted melt infiltration casting was performed to produce composites with 50%, 65%, 75%, and 80% CP-Ti contents. CP-Ti sawdusts were assembled under mechanical pressure in order to attain porous one-piece CP-Ti preforms which were infiltrated by A356 melt at 730 °C under 10−5 Pa vacuum atmosphere. TiAl3 layer was formed at the interface between A356 and CP-Ti phases. Owing to increased diffusion time through decreased diffusion path length, both thickness and hardness of TiAl3 phase were increased with increasing CP-Ti ratio, whereas the best wear resistance was obtained at 65% CP-Ti ratio. The main reason for decrease in wear resistance of 75% and 80% CP-Ti reinforced composites was fragmentation of TiAl3 layer during wear process due to its excessively increased brittleness. Strongly bonded TiAl3 phase at the interface provided better wear resistance, while weakly bonded ones caused to multiply wear rate.

scholarly journals Niobium Additions to a 15%Cr–3%C White Iron and Its Effects on the Microstructure and on Abrasive Wear Behavior

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1321 ◽  
Author(s):  
Arnoldo Bedolla-Jacuinde ◽  
Francisco Guerra ◽  
Ignacio Mejia ◽  
Uzzi Vera
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Abrasive Wear ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Solidification Process ◽  
White Iron ◽  
Bulk Hardness ◽  
Abrasive Wear Behavior ◽  
Cast Alloys

From the present study, niobium additions of 1.79% and 3.98% were added to a 15% Cr–3% C white iron, and their effects on the microstructure, hardness and abrasive wear were analyzed. The experimental irons were melted in an open induction furnace and cast into sand molds to obtain bars of 45 mm diameter. The alloys were characterized by optical and electron microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900 °C for 30 min. Abrasive wear resistance tests were undertaken for the different irons according to the ASTM G65 standard in both as-cast and heat-treated conditions under three loads (58, 75 and 93 N). The results show that niobium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming niobium carbides at the beginning of the solidification process; thus decreasing the eutectic M7C3 carbide volume fraction (CVF) from 30% for the base iron to 24% for the iron with 3.98% Nb. However, the overall carbide content was constant at 30%; bulk hardness changed from 48 to 55 hardness Rockwell C (HRC) and the wear resistance was found to have an interesting behavior. At the lowest load, wear resistance for the base iron was 50% lower than that for the 3.98% Nb iron, which is attributed to the presence of hard NbC. However, at the highest load, the wear behavior was quite similar for all the irons, and it was attributed to a severe carbide cracking phenomenon, particularly in the as-cast alloys. After the destabilization heat treatment, the wear resistance was higher for the 3.98% Nb iron at any load; however, at the highest load, not much difference in wear resistance was observed. Such a behavior is discussed in terms of the carbide volume fraction (CVF), the amount of niobium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.

Infiltration Casting and In Situ Fabrication of NbC Particulates – Reinforced Iron Matrix Composites

2011 ◽  
Vol 284-286 ◽  
pp. 269-272
Author(s):  
Li Sheng Zhong ◽  
Yun Hua Xu ◽  
Na Na Wang ◽  
Xiao Jie Liu ◽  
Fang Xia Ye ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Volume Fraction ◽  
Niobium Carbide ◽  
Wear Testing ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Iron Matrix ◽  
Micro Cracks ◽  
Particulate Reinforced

Niobium carbide (NbC) particulates -reinforced iron matrix composites were prepared by in- situ fabrication method combining an infiltration casting with a subsequent heat treatment. The microstructure and wear-resistance of NbC particulate-reinforced iron matrix composites were studied using scanning electron microscopy, X-ray diffraction, and wear testing. The results indicate that at 1172 °C for 3 hours NbC particulate-reinforced iron matrix composites were fabricated, and the size of NbC reinforcement was 0.3–3.5 μm. The relative wear resistance of the composites was 5.4 times higher than that of gray cast iron under a 20 N load. This was achieved at 22 % NbC volume fraction. Wear of the composites manifests as grooves, broken carbide particulates and some micro-cracks.

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