Synthesis of Al2O3 Reinforced Ti3AlC2 In Situ Composites from Ti, Al, TiO2 and C

2011 ◽  
Vol 480-481 ◽  
pp. 523-526 ◽  
Author(s):  
Jian Feng Zhu ◽  
Lan Ye
Keyword(s):  
Hot Pressing ◽  
Hot Press ◽  
X Ray Diffraction ◽  
Pressing Method ◽  
X Ray ◽  
Tial Intermetallics ◽  
Three Stages ◽  
Hot Press Sintering ◽  
Reactive Hot Pressing

Al2O3 reinforced Ti3A1C2 in situ composites have been fabricated by reactive hot pressing method from the mixture of Ti, Al, TiO2 and C. The phase formation and transformation regularity of samples during the process of hot pressing were investigated in detail by X-ray diffraction (XRD). The microstructures of the synthesized samples were observed by scanning electron microscopy (SEM). The results show that the reactions of powder mixture during the hot press sintering could be divided into three stages: firstly, Ti reacted with Al to form TiAl intermetallics, and Ti reacted with C to form TiC, respectively; and then TiO2 was reduced by Al to form Al2O3, TiAl intermetallics reacted with TiC to form Ti2A1C; finally Ti3A1C2 was formed through the reaction between Ti2A1C and TiC.

Synthesis of Al2O3 Reinforced TiAl Composites from Ti-Al-Nb2O5

2011 ◽  
Vol 239-242 ◽  
pp. 3005-3008
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Fang Ni Du
Keyword(s):  
Hot Press ◽  
X Ray Diffraction ◽  
Pressing Method ◽  
X Ray ◽  
The Matrix ◽  
Different Temperatures ◽  
Reactive Hot Pressing ◽  
Morphology Characteristics ◽  
Scanning Electron

TiAl/Al2O3 in situ composites have been prepared by a reactive hot pressing method from Ti, Al and Nb2O5 powders. The phase transformation and the mechanism of synthesis were studied by differential scanning calorimeter (DSC) of starting powers and X-ray diffraction (XRD) of samples hot press sintered at different temperatures from 500 °C to 1300 °C. Scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was utilized to investigate the morphology characteristics of the products. The resultant in situ formed TiAl/Al2O3 composites exhibited multiplex structures containing TiAl, Ti3Al, Al2O3and NbAl3 phases. Fine Al2O3 particles that act as reinforcing phase are dispersed along the interface of the matrix. The formation of TiAl/Al2O3 composite involves many transitional stages. Firstly, Ti and Al reacted to form TiAl3 and Ti3Al intermediates, then Nb2O5 was reduced by Al to form the Al2O3, and finally, the competitive solid-state diffusing reactions among Ti3Al, TiAl and TiAl3 produced the final matrix phases of the resultant composite.

scholarly journals Microstructure and mechanical properties of Ti3(Al,Ga)C2/Al2O3 composites prepared by in situ reactive hot pressing

2020 ◽  
Vol 9 (6) ◽  
pp. 782-790
Author(s):  
Yuan Fang ◽  
Xiaohua Liu ◽  
Yuxia Feng ◽  
Jianfeng Zhu ◽  
Wei Jiang
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Raw Materials ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reactive Hot Pressing

AbstractIn this study, Ti3(Al,Ga)C2/Al2O3 composites were successfully synthesized by in situ hot pressing at 1350 °C for 2 h using Ti, Al, TiC, and Ga2O3 as raw materials. X-ray diffraction and scanning electron microscopy were used for characterizing the phase identities and microstructures of the sintered composites. The dependence of the Vickers hardness and flexural strength on the Al2O3 content was found to be in single-peak type. Ti3(Al0.6,Ga0.4)C2/10.3vol%Al2O3 composite exhibited significantly improved mechanical properties. Vickers hardness and flexural strength of the composite reached 6.58 GPa and 527.11 MPa, which were 40% and 74% higher than those of Ti3AlC2, respectively. Formation of solid solution and incorporation of second phase of Al2O3 resulted in the opposite influence on the fracture toughness. Finally, the hardening and strengthening mechanisms were discussed in detail.

Fabrication of TiAl/Ti2AlC Composite by Reaction Hot Pressing

2011 ◽  
Vol 52-54 ◽  
pp. 842-845 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Electron Microscopy ◽  
Reaction Process ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Composite ◽  
The Matrix ◽  
Morphology Characteristics ◽  
Scanning Electron

TiAl/Ti2AlC in situ composite was successfully fabricated by hot-press-assisted reaction process from the mixture of Ti, Al and carbon black. The phase formation and transformation were investigated in detail by X-ray diffraction (XRD) and the morphology characteristics were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that when the mixed powders were hot pressed at 1300 °C for 1 h, full dense and highly pure TiAl/Ti2AlC composite was synthesized. The TiAl was the matrix phase and the in situ synthesized Ti2AlC was reinforcing phase. The reaction process was also discussed.

Ti2AlC/TiAl Matrix Intermetallic Compound Prepared by In Situ Hot Pressing

2014 ◽  
Vol 602-603 ◽  
pp. 515-518
Author(s):  
Tao Tao Ai ◽  
Fen Wang ◽  
Chen Hui Yang
Keyword(s):  
Intermetallic Compound ◽  
Hot Pressing ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Pressing Method ◽  
Temperature Oxidation ◽  
Tial Intermetallic Compound ◽  
Increasing Temperature ◽  
Sintered Product

As the new structural material, TiAl intermetallic compound has great potential application in aerospace engine, energy and automotive fields. But the bottleneck problems including poor room temperature ductility and high-temperature oxidation resistance limit its application. Ti2AlC possesses an unusual combination of the merits of both metals and ceramics, which is considered the best reinforcement for TiAl intermetallic compound. In the present work, Ti2AlC/TiAl matrix intermetallic compound was successfully fabricated by in situ hot pressing method from the mixture of Ti/Al/TiC. The phase transitions were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The microstructure of the product was studied by scanning electron microscopy (SEM). Ti reacted with Al liquids to form Ti-Al intermetallics below 900 °C firstly. With increasing temperature (above 900 °C), a part of TiAl intermetallics reacted with TiC to form Ti2AlC reinforcement. The as-sintered product presented dense and typical lamellar structure. The in-situ synthesized fine Ti2AlC contributed to improve the strength of TiAl matrix intermetallic compound.

Fabrication of Nano-MgO Reinforced Fe-Cr-Ni Composites by Reactive Hot Pressing

2009 ◽  
Vol 620-622 ◽  
pp. 551-554 ◽  
Author(s):  
Chang Chen ◽  
Jian Feng Yang ◽  
Ji Qiang Gao ◽  
Cong Yang Chu
Keyword(s):  
Hot Pressing ◽  
Low Temperatures ◽  
Bending Strength ◽  
Exothermic Reaction ◽  
X Ray ◽  
Three Point Bending ◽  
Fine Grained ◽  
In Situ Formation ◽  
Reactive Hot Pressing

The self-propagating combustion reaction 0.741Mg + 0.247Fe2O3 + 0.188Ni + 0.318Cr → 0.741MgO + Fe0.494Ni0.188Cr0.318 was applied to prepare a nano-MgO reinforced Fe-Cr-Ni composite, by reactive hot pressing (RHP) under a condition of 700°C/30MPa/2h. The densification was enabled by the low temperatures produced by the exothermic reaction. According to TG-DTA and X-ray diffractometry (XRD), the highly-exothermic thermite reaction began at about 600°C and the in-situ formation of composites comprised predominantly of (FCC) Cr0.19Fe0.7Ni0.11, (FCC) Fe-Cr, (BCC) MgO and a small quantity of (BCC) MgFe2O4. The Vickers hardness was 3.67GPa, the three-point bending strength was 112.5±10MPa, and the fracture toughness was 3.28 MPa•m1/2. The microstructure of the composite was observed via scanning electron microscopy. This indicated that the distributions of in-situ-formed (BCC) MgO phases (~800 nanometers) were homogeneous into in a matrix of a fine-grained metallic alloy phases that gather together to form agglomerates in the composite.

Microstructure and Mechanical Property of Ti3AlC2/TiAl3 Composite Synthesized by Hot Pressing

2015 ◽  
Vol 816 ◽  
pp. 210-215
Author(s):  
Wei Ping Chen ◽  
Yong Zeng ◽  
Xiao Mei Li ◽  
Hua Qiang Xiao
Keyword(s):  
Hot Pressing ◽  
Bending Strength ◽  
Milling Process ◽  
Toughening Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
New Phase ◽  
Microstructure And Mechanical Property

Ti3AlC2/TiAl3 composite was successfully fabricated by ball milling and in-situ reaction/hot-pressing of Ti, Al and graphite powders mixture at 1200 °C and 30 MPa for 30 min. The phase composition and microstructure of the milled powders and synthesized composite were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the mechanical properties and the toughening mechanism of 20%vol Ti3AlC2/TiAl3 composite was also studied. The results show that no new phase is detected during 50 h of milling process. The in-situ synthesized samples are fully dense and composed of 72%vol TiAl3, 24%vol Ti3AlC2 and 4%vol Al2O3/TiC. The Vickers Hardness, three-point bending strength and fracture toughness of the composite is ~5.2 GPa, ~243 MPa and ~4.3 MPa/m1/2, respectively. Analysis of microstructure reveals that crack deflection, crack bridging and delamination of Ti3AlC2 are the main mechanism responsible for the toughening.

Effect of TiO2 Addition on the Microstructures and Mechanical Properties of γ-TiAl Intermetallics

2011 ◽  
Vol 211-212 ◽  
pp. 205-208 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Jiang Jing Wang
Keyword(s):  
Mechanical Properties ◽  
Strengthening Mechanism ◽  
Reaction Synthesis ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tial Intermetallics ◽  
Universal Properties ◽  
Microstructures And Mechanical Properties ◽  
Particulate Reinforced

Al2O3 Particulate reinforced TiAl based composites have been fabricated by hot press-assisted reaction synthesis (HPRS) method using Ti, Al and TiO2 as starting materials. Effect of the TiO2 addition on the microstructures and mechanical properties of the TiAl/Al2O3 composites were detailedly investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and universal properties tests. The results show that the TiO2 addition has evident effect on phase composition and microstructure of the TiAl intermetallics, as a result, the mechanical properties of TiAl composites are improved. When the TiO2 content is 10.58 wt %, the flexural strength and fracture toughness reach the maximum values of 537.34 MPa and 9.38 MPa·m1/2, which are increased by 70% and 23%, respectively. The strengthening mechanism is also discussed.

Influence of Processing Procedure on Mechanical Properties of A319 by Comparison between Casting and Powder Metallurgy

2016 ◽  
Vol 850 ◽  
pp. 841-845
Author(s):  
Feng Gao ◽  
Cong Xu ◽  
Guo Fu Ji ◽  
Ming Ju Yang ◽  
Chao Li Ma
Keyword(s):  
Powder Metallurgy ◽  
Testing Machine ◽  
Optical Microscope ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy ◽  
Universal Testing ◽  
Processing Procedure ◽  
Hot Press Sintering

Al-6wt.%Si-3.5wt.%Cu alloy (A319) were prepared by casting and powder metallurgy (PM) methods to investigate the influence of processing procedure on properties. The casting samples were cast into a horizontal mold after degassing by argon. The PM samples were extruded after hot-press sintering before which Al-11wt.%Si master alloy powder, pure Al powder and 48 h ball-milled Al-40wt.%Cu powder were blended for 12 h at rotation speed of 250rpm. The samples underwent a T6 temper, i.e. solution, water quenching and artificial aging. Microstructures were observed by optical microscope (OM) and scanning electron microscope (SEM), and phases were determined by X-ray diffraction (XRD). The tensile testing was carried out on universal testing machine. The results showed that heat treatment could greatly improve the tensile strength of the samples, especially for the casting counterpart. Discussion was made to analyze the reason that the properties differed.

BARIUM HEXAFERRITE THICK FILMS BY HOT PRESS SINTERING

2010 ◽  
Vol 24 (06) ◽  
pp. 561-566 ◽  
Author(s):  
H. C. JIANG ◽  
W. L. ZHANG ◽  
Y. HE ◽  
B. PENG ◽  
W. X. ZHANG
Keyword(s):  
Easy Axis ◽  
Thick Films ◽  
Barium Hexaferrite ◽  
Film Plane ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Remanence Ratio ◽  
Magnetic Easy Axis ◽  
Hot Press Sintering

BaFe 12 O 19 ferrite thick films were screen-printed and sintered at 1150°C under pressure (hot press sintering). The effects of the hot press sintering on the properties of barium hexaferrite thick films were investigated. The X-ray diffraction pattern shows improvement of the (00l) texture under pressure. The porosity size of the hot press sintering samples decreases obviously and the surface compactness is improved as the pressure is increased. The films are quite anisotropic with magnetic easy axis perpendicular to the film plane. The largest remanence ratio achieved is 0.75 under the highest pressure of 4 MPa.

Preparation of Si3N4-Al2O3 Functional Gradient Joining Material Using Transient β-Sialon Interlayer

2010 ◽  
Vol 434-435 ◽  
pp. 764-767
Author(s):  
Lin Jiang Wang ◽  
Xiang Li Xie ◽  
Ye Zhang ◽  
Ying Guang Chen
Keyword(s):  
High Temperature ◽  
Fatigue Cracks ◽  
Structure And Properties ◽  
Structural Ceramics ◽  
Hot Press ◽  
X Ray Diffraction ◽  
Gradient Distribution ◽  
X Ray ◽  
Functional Gradient ◽  
Hot Press Sintering

The joining of high temperature structural ceramics to other materials is an important process commercially and technologically. Due to the existence of physical and economic limitations for the manufacture of large parts, joining is essential. Functional gradient materials (FGMs) are designed to exhibit a desirable gradient in a property, due ether to a gradient in composition, or microstructure, or both. In this paper, Si3N4-Al2O3 functional gradient joining material was prepared by hot press sintering of multilayered FGMs with 20 layers of thickness 400um each using β-Sialon as transient interlayer. The structure and properties of the materials were analyzed by the means of scan electron microscopy(SEM), X-ray diffraction(XRD) and micro-sclerometer. The components of the materials have gradient distribution and successional. The microhardness is gradient changing with the change of micro-structure. The interface between layers is tightly coupling and has no stress convergence. The test of thermal shock and fatigue cracks of FGM between 1300 °C and 900 °C show good properties of thermal stress relaxing and resistance for high temperature.

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