The influence of reinforced particle fracture on strengthening of spray formed Cu-TiB {sub 2} composite (original) (raw)
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Purpose: The present work aims to investigate the effect of the reinforcing ceramic particles on the mechanical and tribological properties and microstructure of the steel-TiB 2 composites. Design/methodology/approach: The austenitic AISI316L stainless steel reinforced with 10 vol.% and 20 vol.% TiB 2 particles was produced using the high temperature-high pressure (HT-HP) method. The sintering process was carried out at pressure of 7.0±0.2 GPa and temperature of 1200°C for 60 seconds. Density of sintered materials was measured according to the Archimedes principle. Mechanical properties were determined by Vickers hardness and compression test. The friction coefficient was measured using ball-on-disk method. This tests were realized at room temperature. Microstructural observations were carried out using scanning electron microscopy. Findings: The materials were characterized by very high level of consolidation, which was equal to 96% for composites with 10 vol.% and 20 vol.% TiB 2 particles. The results show that the composites exhibited higher Young's modulus, Vickers hardness and compression strength when compared with conventionally austenitic AISI316L stainless steel. The addition of 20 vol.% of TiB 2 particles to steel caused significant reduction of the values of friction coefficient. The SEM studies of composites allowed to reveal TiB 2 phase along grain boundaries. In case of the composite with 20 vol.% TiB 2 , the continuous layer of ceramic along the grain boundaries was observed. Practical implications: The obtained test results may be used to optimize the sintering process of the steel-TiB 2 composites by high temperature methods. These results may be used to design new materials i.e. austenitic stainless steel reinforced with TiB 2 ceramic. Originality/value: The work provide essential information on the effect of the TiB 2 particles on the mechanical and tribological properties of composites.
Materials Letters, 2002
A copper matrix composite reinforced by in situ TiB nanoparticle was prepared by reactions of B O , carbon and 2 2 3 titanium in copper-titanium melt. The microstructure and mechanical and electrical properties of the as-drawn in situ composite were investigated. The results showed that the in situ-formed TiB particles, which had a size of about 50 nm, 2 exhibited a homogenous dispersion in the copper matrix. Due to their reinforcement, the tensile strength and hardness of the in situ Cu-TiB composite significantly improved. Moreover, the as-drawn in situ composite had a high electrical 2 conductivity. q
Investigation of Mechanical Properties of Al Alloy Composites through in Situ TiB2 Reinforced
IRJET, 2022
The paper explores the arrangement of in situ TiB2 through a substance response among Al, TiO2, and B2O3. The thermodynamic evaluation shows the arrangement of TiB2 through two phases, in particular, a decrease of Ti and B from their oxides followed by the development of TiB2. 53% and 44% expansions in the yield and extreme elastic burdens of the composite supported with 15%TiB2 contrasted with its unreinforced partner have been noticed.
Microstructure changes in TiB2-Cu nanocomposite under sintering
Journal of Materials Science, 2004
Stability and growth of nanoparticulate reinforcements in metal matrix composites during heating are widely studied for dispersion-strengthened alloys, which contain several volume percent of reinforcing phase. When high volume content of nanoparticles distributed within a matrix is concerned results of particles aggregation and growth as well as crystallization mechanisms are not so evident. In this work microstructural evolution under sintering in metal-matrix composite TiB 2-Cu with high volume content (up to 57%) of titanium diboride nanoparticles 30-50 nm in size was investigated. The nanocomposite powders were produced through synthetic method combining preliminary mechanical treatment of initial powder mixtures in high-energy ball mill, self-propagating exothermic reaction and subsequent mechanical treatment of the product. We focused on microstructure changes in TiB 2-Cu nanocomposite consolidated by Spark-Plasma Sintering and conventional sintering and showed that in the former case fine-grained skeleton of titanium diboride is formed with connectivity between particles well established. In the latter case behavior of nanoparticles is surprising: at low temperatures fiber-like structures are formed while increasing temperature causes appearance of faceted crystals. These unusual results allow us to propose the direct involvement of nanoparticles in the processes of crystallization by moving as a whole in the matrix.
Fracture toughness of discontinuously reinforced Al-4Cu-1.5Mg/TiB2 composites
Metallurgical and Materials Transactions A, 1994
The effect of particle size, particle volume fraction, and matrix microstructure on the fracture initiation toughness of a discontinuously reinforced aluminum composite was examined. The composites were A1-4 wt pct Cu-1.5 wt pct Mg reinforced with 0 to 15 vol pet of TiB2 having an average particle diameter of 1.3 or 0.3/zm produced in situ by the XD process. The roomtemperature p_~ne-strain toughness measured using compact tension specimens ranged from 19 to 25 MPaVm. Toughness was adversely affected by increases in TiB2 volume fraction. The fracture toughness of all composites was affected by changes in the matrix microstructure produced by aging. The response of the composites to artificial aging deviates from that of the matrix. Fractography revealed that these composites failed in a ductile manner, with voids initiating at the reinforcing TiB2 particles. The experimentally measured plane-strain toughness properties of A1-4Cu-1.5Mg composites with well-dispersed, 1.3-/xm TiB2 reinforcements agree with the Rice and Johnson model.
Microstructural evolution of copper–titanium alloy during in-situ formation of TiB2 particles
Transactions of Nonferrous Metals Society of China, 2013
Bulk Cu−Ti alloy reinforced by TiB 2 nano particles was prepared using in-situ reaction between Cu−3.4%Ti and Cu−0.7%B master alloys along with rapid solidification and subsequent heat treatment for 1−10 h at 900 °C. High-resolution transmission electron microscopy (HRTEM) characterization showed that primary TiB 2 nano particles and TiB whiskers were formed by in-situ reaction between Ti and B in the liquid copper. The formation of TiB whiskers within the melt led to coarsening of TiB 2 particles. Primary TiB 2 particles were dispersed along the grain boundaries and hindered grain growth at high temperature, while the secondary TiB 2 particles were formed during heat treatment of the alloy by diffusion reaction of solute titanium and boron inside the grains. Electrical conductivity and hardness of the composite were evaluated during heat treatment. The results indicated that the formation of secondary TiB 2 particles in the matrix caused a delay in hardness reduction at high temperature. The electrical conductivity and hardness increased up to 8 h of heat treatment and reached 33.5% IACS and HV 158, respectively.