内应力对高硅铝复合材料热膨胀行为的影响  

Effect of Internal Stress on the Thermal Expansion Behavior of High Silicon Aluminum Composite Materials

作　　者：李艳霞 李海凤 王晓蓓 Li Yanxia;Li Haifeng;Wang Xiaobei(School of Materials Science&Engineering,North China Institute of Aerospace Engineering,Langfang 065000,China;Key Laboratory of Hebei Thermal Protection Materials,Langfang 065000,China)

机构地区：[1]北华航天工业学院材料工程学院,河北廊坊065000 [2]河北省热防护材料重点实验室,河北廊坊065000

出　　处：《北华航天工业学院学报》2024年第5期1-4,共4页Journal of North China Institute of Aerospace Engineering

基　　金：河北省高等学校科学技术研究项目(QN2016206);北华航天工业学院博士基金项目(BKY201402)。

摘　　要：本文以Al-60%Si复合材料为对象,研究了内应力水平对复合材料热膨胀系数的影响。通过测定不同应力状态下试样的平均热膨胀系数,显示高硅铝复合材料的平均热膨胀系数随温度升高而增大,其中试样的初始内应力水平越高,热膨胀系数值越大,增加的速率也越快。对复合材料的微分线膨胀系数研究显示,随温度升高,微分线膨胀曲线分为线性增大、稳定增加和减小三个阶段,它们的温度范围受初始的内应力水平影响显著。采用理论模型计算复合材料的热错配应力,发现在热错配应力作用下铝基体发生屈服应变是膨胀量增加的主要原因,同时硅相和铝基体相在升温过程中会出现“应力交换”效应,使微分线膨胀系数减小,平均热膨胀系数随温度增大的速率减慢。With Al-60% Si composite as the research target,this study focuses on the effect of internal stress level on the coefficient of thermal expansion(CTE).By measuring the average coefficient of thermal expansion of samples under different stress states,it shows that the average CTE of high silicon aluminum composite increases with the temperature rising,and the higher the initial internal stress level of the sample,the greater the value of the CTE and the faster the rate of increase.Study of differential linear expansion coefficient of composite shows that as temperature rises,the differential linear expansion curve is divided into three stages:linear increase,stable increase,and decrease.The temperature range of three stages is significantly affected by the initial internal stress level.The theoretical model is used to calculate the thermal mismatch stress of the composite.Result shows that the yield strain of aluminum matrix under the thermal mismatch stress is the main reason for the increase of expansion.At the same time,the silicon phase and aluminum matrix phase would have a "stress exchange" effect during the heating process,which are the reasons of differential linear expansion coefficient reducing,and the average coefficient of thermal expansion slowing down with the increase of temperature.

关 键 词：内应力 复合材料 热膨胀系数 高硅铝 

分 类 号：TG244[金属学及工艺—铸造]