Friction stir processing

About: Friction stir processing is a research topic. Over the lifetime, 2977 publications have been published within this topic receiving 62158 citations.

High Strain Rate Superplasticity of Mg Based Composites Fabricated by Friction Stir Processing

Abstract: The nano-sized SiO 2 particles were added into the AZ61 Mg alloys via friction stir processing (FSP) to a volume fraction of 5-10%. After four FSP passes, the 10% composites had uniform dispersion of particles and grain size of 0.8 μm. This composite exhibited high strain rate superplasticity, with a maximum ductility of 470% at 1x 10 -2 s -1 and 300°C or 454% at 3 x 10 -1 s -1 and 400° C while maintaining fine grains less than 2 μm in size.

Effects of ball milling and particle size on microstructure and properties 5083 Al–Ni composites fabricated by friction stir processing

Abstract: Ni particles were incorporated in a 5083 Al alloy matrix by friction stir processing (FSP) to fabricate metal particle reinforced composite. During the optimization of the process parameters for uniform particle distribution, it was found that ball-milled finer particles (10 μm) were dispersed more uniformly in the matrix compared to as-received coarse particles (70 μm). Hence, the particles were ball-milled before incorporating into 5083 Al matrix. The finer ball-milled particles were dispersed uniformly, however a thin intermetallic layer was formed at the particle-matrix interface. The layer was found to be Al–Ni intermetallic. When as-received fine particles of similar size (10 μm) were incorporated using the same FSP parameters no such layer was observed in the processed composite. Hence, ball milling of particles influenced the microstructure of the composite. The high-energy state of the ball-milled particles can be attributed to the formation of the interfacial layer. The strength of both the composite was higher compared to the unreinforced 5083 Al alloy. FSP also refined the grain size of the aluminum matrix from 25 µm to 3.5 µm and this also contributed to the strength enhancement of the composites. The strength and ductility of the ball-milled composite were lower as expected compared to the composite with as-received fine Ni particles due to the presence of the interfacial reaction layer.

Improvement of the microstructure and mechanical properties by hybridizing the surface of AA7075 by hexagonal boron nitride with carbide particles using the FSP process

Abstract: In this study, the fabrication of hybrid metal-matrix-surface composites (HMMSC) through the friction stir process (FSP) was investigated, where hexagonal boron nitride (HBN) was used as a continuously reinforced nanoparticle to improve the tribological behavior of AA7075 aluminum alloy. At the same time, silicon carbide (SiC), tantalum carbide (TaC), and niobium carbide (NbC) nanoparticles were used as secondary reinforced particles that exhibited improved resistance to deformation at elevated temperatures, greater chemical stability, and grain growth control. Hybridization was performed by mixing the same percentage of each element with the hBN nanoparticles before depositing them on the surface of AA7075 aluminum alloy. The presence of reinforcing particles was observed using a scanning electron microscope (SEM), and excellent bonding between the reinforcing elements and the AA7075 aluminum alloy was also observed. Observation of the microstructure of the hybrid composites revealed that the reinforcing nanoparticles were uniformly distributed over the stirred zone, with no evidence of an undesirable strong cluster effect. The grain refinement reached a 4000% reduction with respect to base alloy for the hybrid AA7075/BN_TaC composite matrix. The mechanical properties of the optimal hybrid AA7075/BN_TaC, including compressive strength and microhardness, improved by 26.5% and 40%, respectively, compared to the base alloy. In addition, the presence of hexagonal boron nitride nanoparticles significantly improved the wear resistance, and the wear rate was reduced by 14–24 times.

Dynamic restoration and crystallographic texture of a friction-stir processed Al–Mg–SiC surface nanocomposite

Abstract: In this study, SiC nanoparticles (∼50 nm, 3 vol%) are homogenously incorporated within an Al–Mg alloy metal matrix during multi-step friction-stir processing (FSP) to fabricate an Al-matrix surface