(1. 蘭州理工大學(xué) 甘肅省有色金屬新材料省部共建國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050；2. 蘭州理工大學(xué) 有色金屬合金省部共建教育部重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 在玻璃轉(zhuǎn)變溫度以下選擇350、400、475及600 K進(jìn)行1 h的等溫退火，用納米壓痕儀、掃描電鏡等研究Cu基塊狀非晶晶化過(guò)程的力學(xué)性能及變形。Cu基塊狀非晶在納米壓頭作用下體現(xiàn)彈−塑性變形方式，載荷—位移曲線和壓痕周邊多重剪切帶的特征證明了塑性變形的存在。350 K退火試樣具有較大的壓痕硬度HV和彈性模量E值及較小的塑性變形量dn值；400 K退火后，HV和E值顯著減小，dn值明顯增大；475 K退火后，有少量晶體相析出，但合金以非晶的特性為主，HV和E值繼續(xù)減小，dn值繼續(xù)增大；600 K退火后，晶體相進(jìn)一步長(zhǎng)大和析出，其固溶強(qiáng)化和彌散強(qiáng)化使合金的HV和E值有所增加，dn值略有減小。對(duì)塑性變形機(jī)理進(jìn)行了初步分析。
關(guān)鍵字: Cu基塊狀非晶；晶化；納米壓痕；變形；力學(xué)性能
（1. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, China; 2. Key Laboratory of Non-ferrous Metal Alloys, Ministry of Education, Lanzhou University of Technology, Lanzhou 73005, China）
Abstract:350, 400, 475 and 600 K below glass transition temperature were chosen for isothermal annealing for 1 h. Mechanical properties and deformation of Cu-based bulk metallic glasses(BMGs) during crystallization were studied with nanoindentation instrument and scanning electron microscope(SEM). The results indicate Cu-based BMGs deform in elastic-plastic modes under a nanoindenter. Load-displacement curve and multiple shear bands around a nanoindenter confirm the existence of plastic deformation. The sample annealed at 350 K exhibits higher microhardness(HV), elastic modulus(E), and lower plastic deformation(dn); HV and E values decrease and dn value increases significantly at 400 K; crystal phases exist at 475 K, but the major properties of the alloy is amorphous. HV and E values reduce and dn value increases continually; with growth and precipitation of crystal phases at 600 K, solid solution strengthening and dispersion strengthening of the phases slightly augment HV and E values, and reduce dn value. The plastic deformation mechanism during crystallization is preliminarily analyzed.
Key words: Cu-based bulk metallic glass; crystallization; nanoindentation; deformation; mechanical properties
