连续挤压及热处理对H68黄铜组织与性能的影响

Influence of Continuous Extrusion and Heat Treatment on the Microstructure and Properties of H68 Brass

采用光学显微镜、扫描电子显微镜和液晶电子拉力试验机研究了连续挤压和退火处理对H68黄铜的组织、抗拉强度、延伸率和拉伸断口的影响。结果表明,经连续挤压和退火处理后,H68黄铜的延伸率随着退火温度的增加而增加,抗拉强度随着退火温度的增加略有下降;组织主要由粗大的等轴晶经不规则的长条状转变为多个小晶粒包围一个大晶粒的排布;其拉伸断裂方式由准解理断裂经韧窝断裂转变为韧窝-微孔聚集型断裂;具有较好的塑性变形能力,且随着退火温度的增加逐渐提高。

The effect of continuous extrusion and annealing treatment on the microstructure,tensile strength,elongation and fracture surface of H68 brass was investigated by optical microscopy,scanning electronic microscopy and LCD-electronic tensile-testing machine. After continuous extrusion and annealing treatment,the elongation increases and the tensile strength decreases with increasing annealing temperature. The microstructure changes from coarse equiaxed grains through irregular long strips to the distribution of more small grains surrounding a large grain. The fracture mode varies from cleavage fracture through dimple frature to dimple-microvoid coalescence fracture. The plastic deformation ability is high and increases with increasing annealing temperature.