高温退火对Laves相NbCr_2合金性能的影响  

Effect of high-temperature annealing on properties of NbCr_2 alloy

作　　者：邓莉萍[1,2] 鲁世强[2] 林彦[2] 虞文[2] 

机构地区：[1]南京航空航天大学,南京210016 [2]南昌航空大学,南昌330063

出　　处：《粉末冶金技术》2014年第1期48-53,共6页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(51074092);江西省自然科学基金资助项目(20114BAB216012)

摘　　要：对机械合金化+热压制备的Laves相NbCr2合金分别在800℃、1 000℃、1 200℃下进行了30h、50h、100h的真空高温退火试验,研究了高温退火对其性能的影响。结果表明:随着退火温度的升高,NbCr2合金的相对密度逐渐增高;随着退火时间的延长,NbCr2合金的相对密度出现先升后平稳的变化趋势,1 200℃退火100h后,合金的相对密度由退火前的95.75%升高至97.4%;随着退火温度的升高,时间的延长,NbCr2合金的维氏硬度、断裂韧度呈下降的变化趋势,经800℃、1 000℃、1 200℃退火100h后,合金的维氏硬度分别从退火前的8.36GPa下降为7.10GPa、7.03GPa、6.68GPa,断裂韧度则下降为4.10MPa·m1/2、3.73 MPa·m1/2、3.11MPa·m1/2。由于典型的拓扑密排结构,导致NbCr2合金脆性较大,室温压缩试验无明显塑性变形出现;抗压强度随着退火温度的升高、时间的延长明显下降,经800℃、1 000℃、1 200℃退火100h后,合金的抗压强度分别从退火前的1 826MPa下降为1 150 MPa、1 136 MPa、717MPa。Abstract： NbCr2 alloy,which was prepared by mechanical alloying and hot pressing,was high-temperature annealing at 800℃ , 1 000℃ and 1 200 ℃ for 30, 50, 100 h in vacuum experiment, respectively. The effect of high- temperature annealing on properties of NbCr2 alloys was researched. The results show that the relative density of NbCr2 alloy increases with the increasing annealing temperature . Meanwhile, it increases firstly and then tend to be stable with the prolonging annealing time. The relative density of NbCr2 alloy increases from 95.75% to 97.4% after 100 h annealing at 1 200 ℃. Vickers hardness and fracture toughness of NbCr2 alloy decrease with the increase of annealing temperature and annealing time. Vickers hardness changes from 8.36 GPa to 7. 10 GPa, 7. 03 GPa, 6. 68 GPa and fracture toughness reduces to 4. 10 MPa·m1/2 , 3.73 MPa·m1/2 , 3.11 MPa·m1/2 after 100 h annealing at 800℃ , 1 000℃ and 1 200 ℃ , respectively. Due to the brittleness caused by its typical topology tight exhaust structure, no obvious plastic deformation appears during room temperature compression test. The compressive strength declines obviously with the increase of annealing temperature and annealing time. The compressive strength of NbCr2 alloy reduces from 1 826 MPa to 1 150 MPa, t 136 MPa and 717 MPa after 100 h annealing at 800℃ ,1 000℃ and 1 200 ℃ , respectively.

关 键 词：Laves相NbCr2 高温退火 性能 Laves PHASE NbCr2 

分 类 号：TG139.7[一般工业技术—材料科学与工程]