scholarly journals Effect of New Superhard Phases Formation on Properties of Composite Processed by SHS

2012 ◽  
Vol 527 ◽  
pp. 137-142 ◽  
Author(s):  
Lembit Kommel ◽  
Toomas Tamm ◽  
Raido Metsvahi
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Friction Coefficient ◽  
Tribological Behavior ◽  
Dry Sliding ◽  
Initial Powder ◽  
Nitrogen Flow ◽  
Gaseous Nitrogen ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

A composite was produced from initial powder mixture of B4C (70 wt.%) and Al (30 wt. %) with WC-Co additives introduced during ball-milling and acting as catalysts by self-propagating high-temperature synthesis and followed by heat treatment of raw samples under gaseous nitrogen flow at 650, 800, 1000, 1150 and 1450 °C, respectively. Formation of different new superhard phases was detected via XRD investigation and analysis of microstructures. Micromechanical properties were tested by nanoindentation. The tribological behavior in dry sliding conditions of the composite was investigated using the ball-on-disk technique against alumina balls. The friction coefficient of the composite increased and wear rate decreased with formation of c-BC2N, c-BN, B13C2, W2B5, Al3BC, AlN, etc. contents during heat treatment at increased temperatures.

Composite materials based on Al2O3‒SiC‒TiB2 obtained by SHS extrusion and their hightemperature annealing

2021 ◽  
pp. 51-55
Author(s):  
A. P. Chizhikov ◽  
A. S. Konstantinov ◽  
M. S. Antipov ◽  
P. M. Bazhin ◽  
A. M. Stolin
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Pressing Pressure ◽  
Technological Parameters ◽  
Temperature Synthesis ◽  
Shs Extrusion ◽  
High Temperature Synthesis ◽  
Before And After

As a result of the combination of the processes of selfpropagating high-temperature synthesis (SHS) and shear high-temperature deformation, realized in the method of SHS-extrusion, ceramic rods based on Al2O3‒SiC‒TiB2 were obtained. The influence of technological parameters of the process (delay time, pressing pressure) on the length of the obtained rods has been studied. The obtained materials were annealed in the range 1000‒1300 °C, and the microstructure and phase composition of the materials were studied before and after heat treatment.

scholarly journals Al-Ti-B4C materials obtained by high-temperature synthesis and used as a master-alloy for aluminum

2018 ◽  
Vol 243 ◽  
pp. 00010 ◽  
Author(s):  
Ilya Zhukov ◽  
Vladimir Promakhov ◽  
Yana Dubkova ◽  
Alexey Matveev ◽  
Mansur Ziatdinov ◽  
...  
Keyword(s):  
High Temperature ◽  
Burning Rate ◽  
Powder Mixture ◽  
Pure Aluminum ◽  
Al Alloy ◽  
Initial Powder ◽  
Temperature Synthesis ◽  
Al Content ◽  
High Temperature Synthesis ◽  
Al Powder

The paper presents microstructure, composition, and burning rate of Al alloy produced by high-temperature synthesis (SHS) from powder mixture Al-Ti-B4C with different concentration of Al powder. It has been established that the phase composition of materials obtained at gas-free combustion includes TiB2, Al, and TiC. It is shown that Al content growth powder in initial Al-Ti- B4C mixture from 7.5 to 40 wt.% reduces the burning rate of the powder from 9*10-3 to 1.8*10-3 m/s. For the system consisting of 60 wt.% of (Ti + B4C) and 40 wt.% of Al there is the increase in the porosity of the compacted initial powder mixture from 30 to 51 and reduction in the burning rate from 1.8 * 10-3 to 1 * 10-3 m/s. The introduction of 0.2 wt.% of the obtained SHS materials into the melt of pure aluminum causes reduction of the grain size of the resulting alloy from 1200 to 410 μm.

Solid Phase’s Transformations in Boron Carbide Based Composites during Heat Treatment

2008 ◽  
Vol 138 ◽  
pp. 175-180
Author(s):  
Lembit A. Kommel ◽  
Eduard Kimmari
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Boron Carbide ◽  
Environmental Conditions ◽  
Sliding Wear ◽  
Bending Strength ◽  
Reaction Products ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Different Temperatures

Lightweight B4C/Al composites were produced from powders of boron carbide and aluminum by self-propagating high-temperature synthesis (SHS). The effects of postdensification heat treatment at different temperatures and environmental conditions on phase transformations and properties evolution were studied. Heat treatment processing that followed the synthesis was applied using low heating rate in temperature range from 400°C up to 1500°C. An interconnected multiphase (B4C, Al3BC, and c-BN) microstructure was produced in composite as a result of heat treatment at temperatures below 1080°C. The formation of hard and brittle reaction products (AlN, AlB2, Al4C3, and Al8B4C7) at temperatures above 1150°C causes decrease in bending strength and increase in resistance to unlubricated sliding wear.

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