6061铝合金的热损痕迹与受热条件关联性研究

Study on Correlation between Fire Traces and Heating Condition of 6061 Aluminum Alloy

为研究铝合金在火灾高温条件下的热蚀痕迹特征,使用高温辐射热源对6061铝合金板材进行高温辐射实验。通过控制铝合金板材受热温度和时间获得其在火灾中可能出现的痕迹;采用宏观与微观相结合的方法研究了其痕迹特征。结果表明:6061铝合金板材在300~500℃的升温过程中,氧化物薄膜局部区域出现不连续的黑色氧化区,随着温度升高,黑色区域尺寸变大、面积增多。当在500~600℃时,铝合金表面产生不规律的凸起,表面失去金属光泽,由银白色变成灰色。在620~640℃,板材出现熔化的痕迹,表面氧化层颜色加深,在表面形成圆形凸起或颗粒状突起,氧化物薄膜基本失去了平整的状态,由褶皱分为各个独立的小区域;并因为熔化出现典型的孔洞结构。当温度进一步升高(700℃),再次恢复金属光泽,氧化膜同时出现褶皱区和平整区。本文的研究结果可为火灾调查现场勘验识别铝合金材料相关痕迹特征提供指导。

In order to study the trace characteristics of aluminium alloy in fire,high temperature radiation experiments of6061 aluminium alloy sheet were carried out by using high temperature radiation heat source.By controlling the heating time and temperature,the possible traces of aluminium alloy sheet in fire were obtained.The trace characteristics were studied by combining macro and micro methods.The results show that discontinuous black oxidation zones appear in the local area of oxide films from 300℃to 500℃.With the increase of temperature,the size and area of black oxidation zones become larger and larger.When the temperature ranges from 500℃to 600℃,irregular bulges occur on the surface of aluminium alloys and the surface loses its metallic luster and turns from silver to gray.At 620-640℃,the melting trace of the sheet occurs,the color of the oxide layer on the surface deepens,forming a round or granular protuberance on the surface.The oxide film basically loses its flat state,which is divided into individual small areas by folds,and the typical pore structure appears due to the melting process.When the temperature rises furtherly(700℃),the metallic luster is restored again,and the folded zone and flat zone appear in oxide films.The results of this research can provide guidance for identifying the relevant trace characteristics of aluminium alloy materials in fire investigation.