ZL111铝合金液压制动主缸的开裂分析

ZL111铝合金液压制动主缸体在外观检测时发现主缸开裂,密封检测漏气.为查找铝合金主缸开裂原因,对主缸裂纹、断口形貌、显微组织进行观察,检测其化学成分、相变点.结果表明,主缸的失效是因为组织存在过烧缺陷,降低了材料强度,且晶界存在呈圆角状分布的脆性共晶硅相,并聚集长大,进一步弱化晶界.在淬火应力作用下,缸体开裂,后续加...

Cracking analysis of ZL111 aluminum alloy hydraulic brake master cylinder

ZL111 aluminum alloy hydraulic brake master cylinder was found cracking during the appearance inspection, and seal inspection revealed its leakage. In order to find out the reasons for the cracking of the cylinder, the cracks, fracture morphology and microstructure of the cylinder were observed, and its chemical composition and phase transition point were detected. The results show that the failure of the cylinder is due to the presence of over burning defects in the structure, which reduces the strength of the material. The rounded and brittle eutectic silicon phase is distributed in the grain boundary, which aggregates and grows, and further weakens the grain boundary. Under the effect of quenching stress, the cylinder cracks, and the cracks expand to macroscopic cracks during the subsequent processing. It is discussed and analyzed that the root cause of the cracking of the cylinder is the high content of Mg element in the composition, which reduces the temperature that limits to cause over burning.