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本文研究了两种美国牌号,C67300和C67400的高抗拉黄铜的微观组织。两种合金的铸态和挤压态组织均由富铜的面心立方α相、有序B_2结构的β′相和六方D8_8结构的硅化物Mn_5Si_3组成。在合金C67300中,Mn_5Si_3颗粒呈均匀分布,而C67400中Mn_5Si_3相对集中地分布于β′相晶界上。Mn_5Si_3颗粒既形成于液相,同时也大量析出于过饱和的固相。由于Mn_5Si_3颗粒具有极高的显微硬度,这导致了合金的强度和耐磨性能的提高。
This article studies the microstructure of two high-tensile brass brackets of the US grades C67300 and C67400. The as-cast and extruded microstructures of the two alloys consist of Cu-rich face-centered cubic α phase, β ’phase of ordered B_2 structure and silicide Mn_5Si_3 of hexagonal D8_8 structure. In the alloy C67300, Mn_5Si_3 particles are uniformly distributed, whereas C_4400 Mn_5Si_3 is relatively concentrated on the β ’phase boundary. Mn_5Si_3 particles both formed in the liquid phase, but also a lot of precipitation in the supersaturated solid phase. Due to the extremely high microhardness of the Mn_5Si_3 particles, this leads to an increase in the strength and wear resistance of the alloy.