Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution

Review on ultra-high temperature boride ceramics

Effect of multi-pass friction stir processing on the microstructure, mechanical and wear properties of AA5083/ZrO2 nanocomposites

Influence of boron nitride nanoparticles on microstructure and wear behavior of AA6082/TiB2 hybrid aluminum composites synthesized by friction stir processing

Friction stir processing (FSP) is a rapidly emerging newer solid-state technique for composite fabrication. It involves surface modification which in turn enables successful adaptation of surface p...

A Review of Recent Progress in Solid State Fabrication of Composites and Functionally Graded Systems Via Friction Stir Processing

In this study, surface hybrid composite was fabricated on Al6061 base sheets using friction stir processing (FSP). Samples were subjected to various numbers of FSP passes from one to four with Al2O3/TiB2 powder. Influence of number of FSP passes was studied on distribution of Al2O3/TiB2 particles in aluminium matrix, microstructure, hardness, and wear properties of specimens. The results showed that increase in the number of passes causes a more uniform dispersion of composite particles and thus, decreases particles clustering. In addition, an increase in the number of FSP passes was found to decrease the matrix grain size of the surface hybrid composite. It was observed that the hardness increased as the number of passes increased due to presence and pinning effect of hard Al2O3/TiB2 particles. Also, at higher number of passes, the surface hybrid composite wear resistance was increased.

Wear properties of Al–Al2O3/TiB2 surface hybrid composite layer prepared by friction stir process

Synthesis and sintering of TiB2 nanoparticles

Synthesis and sintering of an alumina /titanium diboride nano-composite have been studied as an alternative for pure titanium diboride for ceramic armor applications. Addition of TiB 2 particles to an Al 2 O 3 matrix can improve its fracture toughness, hardness and flexural strength and offer advantages with respect to wear and fracture behavior. This contribution, for the first time, reports the sintering, microstructure, and properties of Al 2 O 3 –TiB 2 nano-composite densified with no sintering aids. Nano-composite powder was produced by combination of sol–gel and mechano-chemical methods. The densification experiments were carried out using both hot pressing and pressureless sintering routes. In the pressureless sintering route, a maximum of 92.3% of the theoretical density was achieved after sintering at 1850 °C for 2 h under vacuum. However, hot pressing at 1500 °C for 2 h under the same condition led to achieving a 99% of the theoretical density. The hot pressed Al 2 O 3 –TiB 2 nano-composites exhibit high Vickers hardness (16.1 GPa) and a modest indentation toughness (~ 4.2 MPa.m 1/2 ).

Sintering of Al2O3–TiB2 nano-composite derived from milling assisted sol–gel method

Alumina-titanium diboride nano-composite powder was prepared from TTIP and boron oxide using a sol–gel method followed by mechano-chemical reduction in the presence of Al. Optimum weight ratio of B 2 O 3 :TTIP in solution was 1:3. The XRD results reveal that mechano-chemical reduction of the gel resulted in the formation of TiB 2 and Al 2 O 3 after 30 h milling. Also, FTIR spectroscopy of 30 h milled product seams to confirm the formation of TiB 2 and Al 2 O 3 phases in the final product. Scanning electron microscopy showed that the product has a wide range of particle size between 100 nm–2 μm. Transmission electron microscopy study of the product revealed a microstructure in which TiB 2 particles dispersed in Al 2 O 3 matrix with a crystallite size of 10–30 nm. The homogeneity of the composite powder and low temperature of the process distinguished the present study from the previous researches.

Amin Rabiezadeh

Papers

Wear properties of Al–Al2O3/TiB2 surface hybrid composite layer prepared by friction stir process

Synthesis and sintering of TiB2 nanoparticles

Sintering of Al2O3–TiB2 nano-composite derived from milling assisted sol–gel method

Preparation of alumina/titanium diboride nano-composite powder by milling assisted sol–gel method

Microstructural evaluation and tribological properties of underwater friction stir processed CP-copper and its alloy