Hot Shortness of α-Brass

Abstract

centration at grain boundary due to piled up dislocations, local mml migration of grain boundary occurs, revealing corrugated shape of grain boundary. The abnormal hardening of grain-inside will promote the grain boundary sliding, by which W-type cracks or voids are formed along the corrugated boundary or at the triple point of boundaries. The interlinking of those cracks forms and the extensive migration of grain boundaries may dissipate the stress concentration and the crack growth along grain boundaries, leading to the recovery of ductility. Those behaviors are confirmed by the present metallographic study through optical micrography and electron fractography. (Received_January 20, 1970) ally been attributed to the impurities segregated on grain boundaries. Scientific researches in this regard so far has remained far from touching the core of the. matter.

Intermediate temperature embrittlement of copper alloys

“…4a). The recorded ductility trough also increases in width and depth as the alloy grain size increases for brasses, 8,143,150,[170][171][172][173]181,182 bronzes 3,174,175 (Fig. 11), and cupro-nickel alloys.…”

“…As for pure copper 6,9,90,[125][126][127][128][129] and except for very rapid (impact) deformation, as the strain rate increases the trough narrows and becomes more shallow for brasses 68,125,126,128,137,143,150,[170][171][172][173] , bronzes 174,175 , cupro-nickel alloys 9, 176-178 and dispersion hardened copper 6,153,160,179,180 . For two (70-30 and 80-20) a-brasses, T E was found to be strain-rate dependent, but not T R 171 .…”

“…In these alloys intergranular fracture is promoted by a high elastic anisotropy, and is also influenced by the various (brittle or ductile) second phases that can line grain boundaries. [164][165][166][167][168][169] Influence of strain rate and grain size As for pure copper 6,9,90,[125][126][127][128][129] and except for very rapid (impact) deformation, as the strain rate increases the trough narrows and becomes more shallow for brasses, 68,125,126,128,137,143,150,[170][171][172][173] bronzes, 174,175 cupronickel alloys 9,[176][177][178] and dispersion hardened copper. 6,153,160,179,180 For two (70-30 and 80-20) a-brasses, T E was found to be strain-rate dependent, but not T R .…”

“…3,8,107,127,134,143,150,[170][171][172][173][174][175][176][177][181][182][183][184] , even though this is not expected based on simple reasoning (since neither grain boundary voiding nor creep rates in the range of stresses near the transition between intracrystalline and intercrystalline fracture,Fig. 4, -i.e.…”

Machinable Leaded and Eco-Friendly Brass Alloys for High Performance Manufacturing Processes: A Critical Review

“…Hot-shortness occurs during the extrusion process in cases where the extrusion temperature is amplified due to the friction between the billet and the container. In turn, this causes SPPs with a low melting point such as Pb particles and regions exhibiting notable chemical segregation to partially melt or become hot short resulting in the possible formation of tears in close proximity to the metal surface [45,86,88]. In cases where novel brass compositions are designed, aiming to replace the Pb particles with a different type of SPPs, this failure mode becomes particularly important.…”