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.

Microstructural evaluation and corrosion properties of aluminium matrix surface composite adding Al-based amorphous fabricated by friction stir processing

Abstract: A novel aluminium matrix surface composite adding Al84.2Ni10La2.1 amorphous, which the layer depth was 5 mm, was fabricated by friction stir processing. The surface composite region shows obvious sandwich structure. The average hardness of the surface composite is about HV97, higher than the base metal is about HV80. The maximum tensile strength of the processed aluminium plate with the surface composite is 410 MPa. The surface composite was mainly composed of phases α-Al, Mg2Al3, MnAl6 and La3Al11. The surface composite added the amorphous strip had the lower icorr, corrosion current density, and the higher passivation current than the surface composite not added amorphous strip. And there is obvious passivation zone for the surface composite. However, a large number of ultrafine grained which was composed of the α-Al and α-Al amorphous structures can be observed in the surface composite. And the grain size range of them is 90–400 nm. It is conceivable that the existence of these ultrafine grained structures and change of crystal plane would contribute greatly to improve the mechanical properties and corrosion resistance of the aluminium matrix surface composite.

Strengthening mechanism of friction stir processed and post heat treated NiAl bronze alloy: Effect of rotation rates

Abstract: In this work, NiAl bronze (NAB) alloys were subjected to friction stir processing (FSP) at a constant traverse speed of 100 mm/min and rotation rates of 600 rpm, 800 rpm, 1000 rpm and 1200 rpm, respectively. Thereafter, heat treatment was performed at 675 °C for 2 h. The effects of rotation rates on strengthening mechanisms of friction stir processed and post heat treated NAB alloy were studied. The results showed that friction stir processed NAB alloy microhardness was increased as the rotation rate increased. During friction stir processing, martensite nanotwins could be formed due to high strain rates and peculiar martensitic structures of NAB alloys. A rotation rate increase, increased peak temperatures and strain rates in friction stir processed NAB alloys, leading to a significant amount of martensite nanotwins formation. As rotation rates increased from 600 rpm to 1200 rpm, in addition to grain refinement effects, the strengthening mechanism of friction stir processed NAB alloys gradually changed from secondary phase strengthening to solid solution, dislocations and nanotwin strengthening. During post heat treatment, discontinuous static recrystallization occurred and β′ phase decomposed into α and κ phases. Highest microhardness values were obtained at the rotation rate of 800 rpm and the uniformly distributed second phases formed during friction stir processing contributed mainly to higher microhardness.

A Review of Friction Stir Processing of Structural Metallic Materials: Process, Properties, and Methods

Abstract: Friction stir processing (FSP) has attracted much attention in the last decade and contributed significantly to the creation of functionally graded materials with both gradient structure and gradient mechanical properties. Subsurface gradient structures are formed in FSPed metallic materials due to ultrafine grained structure formation, surface modification and hardening with various reinforcing particles, fabrication of hybrid and in situ surfaces. This paper is a review of the latest achievements in FSP of non-ferrous metal alloys (aluminum, copper, titanium, and magnesium alloys). It describes the general formation mechanisms of subsurface gradient structures in metal alloys processed by FSP under various conditions. A summary of experimental data is given for the microstructure, mechanical, and tribological properties of non-ferrous metal alloys.