摘要
采用放电等离子脉冲烧结（SPS）方法制备了接近致密的Fe-Ni/ZrW2O8复合材料。当复合材料温度高于117℃,复合材料的-γZrW2O8转变为-αZrW2O8,并发生显著的体积膨胀,降温过程中基体与ZrW2O8之间不断增加的热应力又使-αZrW2O8变为-γZrW2O8。添加10%（体积）和25%%（体积）ZrW2O8的样品在40~100℃温度区间膨胀系数与基体相同,这是由于金属基体中发生的塑性变形抵消了一部分ZrW2O8的负膨胀效果。温度升高时ZrW2O8发生γ-α相变后,产生的体积膨胀使基体发生加工硬化,由于金属基体塑性形变对膨胀系数的影响会减弱。复合材料在200~300℃温度区间内的膨胀系数随ZrW2O8含量的增加而降低。
Nearly dense Fe-Ni/ZrW2O8 composite was fabricated using spark plasma sintering process.When heating to above 117 ℃,phase transformation from γ-ZrW2O8 to α-ZrW2O8 produces great volume increase.In cool down process,the increasing thermal stress between matrix and ZrW2O8 creates the transformation from α-ZrW2O8 to γ-ZrW2O8.Sample adding 10 vol% and 25 vol% ZrW2O8 shows nearly the same thermal expansion coefficient between 40 ℃ and 100 ℃ compared to the matrix,because the negative thermal expansion were canceled out by the plastic deformation of metal matrix.When heating lead to phase transformation from γ-ZrW2O8 to α-ZrW2O8,the great volume increase of ZrW2O8 induces work hardening in the metal matrix,then the influence of matrix plastic deformation on thermal expansion coefficient are weakened.The thermal expansion coefficient of the composites between 200 and 320 ℃ decreases with the content of ZrW2O8 increasing.
出处
《金属功能材料》
CAS
2011年第3期36-40,共5页
Metallic Functional Materials
