摘要
针对目前W-Cu功能梯度材料(FGM)在长期热震循环过程中的稳定性缺乏相应研究的问题,以化学镀W-10wt%Cu复合粉体和Cu粉为原料,通过叠层压制和常压气氛烧结的工艺制备了W-10wt%Cu/W-20wt%Cu/W-30wt%Cu层状梯度材料。在600℃、800℃、1000℃温度下进行热震试验,对试样在不同热震温度、热震次数下的显微组织和热学性能变化进行了研究。试验结果表明,随着热震温度升高,渗出至试样各梯度层表面的Cu逐渐增加。当热震温度达到1000℃时,试样各梯度层表面出现大量Cu聚集成片的现象,同时在W-20wt%Cu/W-30wt%Cu界面处发现了界面裂纹。随着热震次数的提高,在W-10Cu层中,Cu逐渐渗出表面并在内部留下微孔。此外,W-Cu FGM的热导率随热震次数的增加而减小,在1000℃经过200次热震后,室温热导率由200.54 W·(m·K)^(−1)降至159.23 W·(m·K)^(−1),降低了20.60%。该结果揭示了热震循环中裂纹形成与显微组织变化的耦合失效机制,明确了W-Cu FGM安全服役的范围。
In order to investigate the safe service range of W-Cu functionally graded material(FGM)in the cyclic thermal shock process,layered W-10wt%Cu/W-20wt%Cu/W-30wt%Cu gradient materials were prepared by laminated pressing and atmospheric sintering using electroless W-10wt%Cu composite powder and Cu powder as raw materials.Thermal shock experiments were carried out under temperature differences of 600℃,800℃and 1000℃.The microstructure and thermal properties of the sintered gradient samples were investigated under different thermal shock temperatures and times.The experimental results show that with the increase of thermal shock temperature,Cu gradually exudes to the surface of each gradient layer.When the thermal shock temperature reaches 1000℃,a large number of Cu appear in clumped sheets on the surface of each gradient layer.Simultaneously,interface cracks are found at the interface of W-20wt%Cu/W-30wt%Cu.With the increase of the number of thermal shock times,in the W-10wt%Cu layer,the Cu exudation surface leaves micro pores in the interior.In addition,the thermal conductivity of W-Cu FGM decreases with the increase of thermal shock times.After thermal shock at 1000℃for 200 times,the thermal conductivity of room temperature drops from 200.54 W·(m·k)^(−1) to 159.23 W·(m·k)^(−1),decreasing by 20.60%.This result reveals the coupling failure mechanism of crack formation and microstructure changes in thermal shock cycles,and clarifies the scope of safe service of W-Cu FGM.
作者
徐仙
陈鹏起
台运霄
魏邦争
卫陈龙
程继贵
Xian XU;Pengqi CHEN;Yunxiao TAI;Bangzheng WEI;Chenlong WEI;Jigui CHENG(School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China;Research Center of Powder Metallurgy Engineering and Technology of Anhui Province,Hefei 230009,China;National-Local Joint Engineering Research Center of Nonferrous Metals and Processing Technology,Hefei 230009,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2021年第12期4205-4211,共7页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(51674095
52004079)
国家重点研发计划(2018YFC1901704)。
关键词
W-Cu合金
功能梯度材料
热震
显微组织
热导率
W-Cu alloy
functionally graded material
thermal shock
microstructure
thermal conductivity
