Challenges of the study on precipitation behaviors of MnS in oriented electrical steels

Materials Science and Engineering: A

Atsumi

et al. 2012

The effects of Ti and Sn alloying elements on the microstructural and mechanical properties of 60/40 brass were studied by powder metallurgy processing. The supersaturated solid solution of Ti creates a high precipitation reaction chemical potential in water-atomized BS40-1.0Ti brass powder. Consequently, BS40-1.0Ti brass was remarkably strengthened by the addition of Ti. However, Ti readily segregated in the primary particle boundaries at elevated temperatures, which detrimentally affected the mechanical properties of BS40-1.0Ti brass. Accordingly, Sn was proposed as an additive to BS40-0.6Sn1.0Ti to inhibit the segregation of Ti. Consequently, the Ti precipitate was retained in the form of CuSn 3 Ti 5 in the interior of grains and grain boundaries rather than in the primary particle boundaries. This result demonstrates that the addition of Sn can effectively hinder Ti segregation in the primary particle boundaries. Sn addition produced significant grain refinement and mechanical strengthening effects in BS40-0.6Sn1.0Ti brass. As a result, outstanding strengthening effects were observed for BS40-0.6Sn1.0Ti sintered at 600 C, which exhibited a yield strength of 315 MPa, an ultimate tensile strength of 598 MPa, and a Vickers micro-hardness of 216 Hv. These values represent increases of 27.5%, 20.1% and 45.6%, over those of extruded BS40-1.0Ti brass.

Section: Discussionmentioning

confidence: 99%

The effects of Ti and Sn alloying elements on precipitation strengthened Cu40Zn brass using powder metallurgy and hot extrusion

Materials Science and Engineering: A

Atsumi

et al. 2012

“…However, the possible recovery or dynamic recrystallization induced by hot deformation at higher temperature might reduce the dislocation density [28,29]. Recrystallization of a phase occurred at higher sintering temperature induces a decrease of dislocation density, which has strong effects on the precipitation behaviors of CuSn 3 Ti 5 particles, thereby engendering segregation of Ti precipitates at primary particle boundaries, resulting in decrease of the hardness.…”

Section: Discussionmentioning

confidence: 99%

Development of precipitation strengthened brass with Ti and Sn alloying elements additives by using water atomized powder via powder metallurgy route

Materials Chemistry and Physics

Kondoh

et al. 2012

h i g h l i g h t s g r a p h i c a l a b s t r a c t < Alloying elements Ti and Sn are proposed as additives in 60/40 brass. < Super-saturated Ti in powder creates high chemical potential for precipitation. < CuSn 3 Ti 5 precipitates demonstrated significant grain refinement. < Ti and Sn showed remarkable strengthening effect. a b s t r a c tEffect of Ti and Sn alloying elements on microstructure and mechanical properties of 60/40 brass has been studied via the powder metallurgy (P/M) route. The water-atomized BS40e0.6Sn1.0Ti (Cu40wt%Zn e0.6wt%Sn1.0wt%Ti) pre-alloyed powder was consolidated at various temperatures within range of 400 e600 C using spark plasma sintering (SPS) and hot extrusion was carried out at 500 C. Effects of extrusion temperature on microstructure and tensile strength were investigated by employing SEM-EDS/ EBSD, TEM, XRD and tensile test. Results indicated that super-saturated solid solution Ti and Sn elements created high chemical potential for a precipitate reaction in rapidly solidified brass powder, which showed significant strengthening effects on the extruded sample consolidated at lower temperature. Solid solubility of Ti in brass matrix decreased with increasing of sintering temperature, thus resulted in degradation of mechanical properties. Consequently, lower hot processing temperature is necessary to obtain excellent mechanical properties for BS40e0.6Sn1.0Ti during sintering and extrusion. An yield strength of 398 MPa and ultimate tensile strength of 615 MPa were achieved, they respectively showed 31.3% and 22.9% higher values than those of extruded Cu40Zn brass.

“…It is appreciated that a lower preheating temperature is necessary for excellent properties of the wrought alloys. Additionally, the possible recovery or dynamic recrystallization induced by hot deformation at higher temperatures might reduce the dislocation density [19,20]. The recrystallization that occurs after hot-extrusion decreases the dislocation density, which strongly affects the mechanical behaviors of BS40-X.…”

Section: Discussionmentioning

confidence: 99%

Dependence of microstructure and mechanical properties on hot-extrusion temperatures of the developed high-strength Cu40Zn–CrFeTiSn brass by powder metallurgy

Materials Science and Engineering: A

Kondoh

et al. 2012

a b s t r a c tEffect of extrusion temperature on the microstructure and mechanical properties of the powder metallurgy Cu40Zn-CrFeTiSn alloy were investigated, through analysis on the solid solution of alloying elements, phase transformation and precipitation behavior. The extrusion was carried out between 500 1C and 650 1C using an extrusion ratio of 37:1. After extrusion, the microstructure was found consisting of the dual aþb phase structure and precipitates dispersing uniformly in the matrix. The tensile strength gradually decreased when the extrusion preheating temperature was increased. Solid solubility of Ti and Cr decreased steadily and grain coarsening occurred with increase in the extrusion temperature. Consequently, the lower extrusion preheating temperature was necessary to obtain excellent final mechanical properties, thus the extrusion temperature of 500 1C was enough to produce good ductility while maintaining the promising values of mechanical properties after extrusion.