Fabrication of Steel Matrix Composite Locally Reinforced with in Situ TiB₂ Particulate using Self–Propagating High–Temperature Synthesis Reaction of Ni–Ti–B System During Casting

Abstract

plasma plume. To achieve a columnar porous structure as well as a high growth rate of the thicker pc-ZrO 2 layer, a pulsed 1 kW laser was applied. The irradiation parameters (pulse duration 1 ms, power density 10 5 W/cm 2 ) were chosen such that conventional thermal evaporation without plasma formation occurred. The targets for the ZrO 2 deposition were pressed and sintered from amperite powder (Y 2 O 3 : 7.79 wt%, HfO 2 : 1.84 wt%, SiO 2 : 0.20 wt%, ZrO 2 : remaining).Investigation of Boundary Layer Reactions: By means of PLD with a relatively high pulse energy of 800 mJ and stronger focusing, the generation of otherwise undesired droplets of the target material is forced. Since the directional characteristic of the droplets differs from that of the plasma plume, the substrate can be arranged in such a way that predominantly droplets are deposited. Due to the high kinetic energy of the droplets, they are flattened on impact before they solidify. The resulting Al and Ti hillocks are typically 2 to 20 lm in diameter and 0.5 to 5 lm high. (Fig. 2) After droplet deposition, the Al/Cu and Ti/Cu samples were tempered (773 / 823 K, 100 / 300 min, atmosphere Ar 4.8, 10 5 Pa). The resulting composition changes were examined by EDX in the SEM and also by AES depth analysis. The preparation of cross-sections of deposited droplets by ion milling with 7 keV Kr ions proved to be particularly useful (Fig. 3). At such cross sections, the chemical composition in the vicinity of the interface was measured by EDX.Investigation of Roughness effects: Roughness values R a of the copper substrate between 0.03 and 1.1 lm were prepared using appropriate grinding agents (abrasive paper, grit size P80 to P2500). The roughness was determined by a mechanical profiler (MAHR Perthometer S8P) and averaging over typically three samples polished in the same manner.Bending bars with the dimensions 30 4.5 3 mm 3 were coated onto one face with an area of 30 4.5 mm 2 . These samples were then deformed by means of four-point bending where the coated surface was chosen as side face of the bending bar (cf. Fig. 4). Due to the bending deformation of the substrate, the coating is simultaneously subjected to a tensile load (Fig. 4, upper side) and a compressive load (lower side). To characterise the coating adherence quantitatively, the maximum substrate strains on the upper and lower sides of the bending bars were used. In particular, the critical spallation strains were determined where in the course of bending first spallings were visible to the naked eye under tensile and compressive load, respectively.Metal matrix composites (MMCs) are a class of materials that seek to combine the high strength and stiffness of a ceramic with the damage tolerance and toughness provided by a metal matrix. [1,2] Although most of the studies on MMCs are centered on the lightweight engineering materials titanium, aluminum and magnesium due to their attractive combination of improved mechanical properties and weight-saving potential, [3±5] there is also significant inter...

Effect of Ni content on the products of Ni–Ti–B system via self-propagating high-temperature synthesis reaction

“…4(a-e) shows the typical FESEM of the SHS reaction products synthesized by green preforms with a molar ratio of B/Ti = 2.0 with (a) 30, (b) 40, (c) 50, (d) 60 and (e) 70 wt.% Ni, respectively. It can be observed that large amounts of TiB 2 particulates with the morphology of hexagonal-prism have been synthesized as designed, which is accordant with the results of the study of Horlock et al [3] and our previous study [28,29]. The average sizes of normal TiB 2 particulates are nearly the same and about 4-6 m in the products of 30, 40 and 50 wt.% Ni-Ti-B systems.…”

In Situ Synthesis of Ti5Si3 Intermetallic Particulate Locally Reinforced Medium Carbon Steel-matrix Composite via the SHS Reaction of Fe–Ti–Si System during Casting

“…2 in Ref. 11). Subsequently, the medium carbon steel melt, which composition is measured by an ARL4460 Metals Analyzer and shown in Table 1, prepared by non-oxidation process in a 5 kg medium-frequency induction furnace with a temperature of about 1 600°C was poured into the mold to ignite the SHS reaction of the preforms.…”

“…[6][7][8][9] Moreover, the high-volume fraction of reinforcement distributed only in the local region, which is difficult to or even cannot be realized in the monolithic composite fabricated by conventional casting route due to the poor castability, indicates that the locally reinforced composite is a promising type of material for the reason that it offers a virtually unique combination of low cost and high-wear resistance. 10,11) Furthermore, the majority of iron-and steel-based composites focus on using ceramic particulates, i.e. TiB 2 , TiC, VC, Cr 3 C 2 , etc., 4,8,[9][10][11][12][13][14][15][16][17] as the reinforcements, primarily due to their capability of greatly improving the hardness and wear resistance of the materials.…”

“…10,11) Furthermore, the majority of iron-and steel-based composites focus on using ceramic particulates, i.e. TiB 2 , TiC, VC, Cr 3 C 2 , etc., 4,8,[9][10][11][12][13][14][15][16][17] as the reinforcements, primarily due to their capability of greatly improving the hardness and wear resistance of the materials. However, little attention has been paid to the intermetallic particulate reinforced steel matrix composite.…”

In Situ TiC/TiB2 Particulate Locally Reinforced Steel Matrix Composites Fabricated Via the SHS Reaction of Ni–Ti–B4C System

“…Recently, the combination of self‐propagating high‐temperature synthesis (SHS) and traditional casting routes provides an easy process to produce ceramic particulate reinforced steel matrix composites 1–15 . Among these composites, in situ ceramic particulate locally reinforced steel matrix composite may be one of the most promising composites which can be widely used in the practical application of excellent wear resistance and/or cutting performance with improved toughness such as pistons, brakes rotor, and mining machine, etc 4–10 .…”