热处理对铸态Fe-Cr-W-B合金微观结构与力学性能的影响  

Effect of heat treatment on microstructure and mechanical properties of as-cast Fe-Cr-W-B alloy

作　　者：侯浪 李军[1] 刘颖[1] HOU Lang;LI Jun;LIU Yin(School of Materials Science and Engineering,Sichuan University,Chengdu 610065,Sichuan,China)

机构地区：[1]四川大学材料科学与工程学院,四川成都610065

出　　处：《四川冶金》2024年第4期67-71,共5页Sichuan Metallurgy

摘　　要：Fe-W-B系合金具有优异的核辐射屏蔽效果,在添加一定量的Cr元素后,原本粗大的脆性硼化物组织得到了一定的细化,但其塑韧性等力学性能依然较差。为进一步改善Fe-Cr-W-B合金的微观结构和力学性能,本文引入1200℃保温1 h的热处理工艺,研究其对铸造Fe-Cr-W-B合金微观结构和力学性能的影响。结果表明,铸态Fe-Cr-W-B合金以α-(Fe,Cr,W)为基体,以M_(3)B_(2)(M=W,Cr,Fe)为硼化物析出相,硼化物在晶界处呈连续网状分布,因而合金在变形过程中易形成应力集中而产生微小裂纹以致断裂,使得Fe-Cr-W-B合金塑韧性极差。经过1200℃保温1 h的热处理后,Fe-Cr-W-B合金基体中的过饱和W原子扩散进入硼化物,基体的固溶强化效应减弱,硬度降低,合金强度略有下降;但硼化物体积收缩,晶界处的连续网状结构断开,硼化物弥散分布,Fe-Cr-W-B合金的塑韧性得到较大改善。Fe-W-B alloys have excellent nuclear radiation shielding effect,but poor mechanical properties.The Fe-Cr-W-B alloy powder produced by adding Cr element has relatively fine boride microstructure.In order to further im-prove the microstructure and mechanical properties of FeCr-W-B alloy,this paper investigates the effect of heat treatment at 1200℃for 1 h on the microstructure and mechanical properties of cast Fe-Cr-W-B alloy.The results show that the as-cast Fe-Cr-W-B alloy is composed ofα-(Fe,Cr,W)as matrix and M_(3)B_(2)(M-W,Cr,Fe)as boride precipitated phase.The boride is distributed in a continuous network at the grain boundary,which causes stress con-centration in the matrix during deformation,resulting in extremely poor ductility and toughness of Fe-Cr-W-B alloy.After heat treatment at 1200℃for lh,W atomsin Fe-Cr-W-B alloy matrix enterstheboride,solid solution strengthening effect is weakened,reducing the hardness and strength;the boride volume shrinks,the continuous mesh structure at the grain boundary is broken,and the ductility and toughness of Fe-Cr-W-B alloy is improved.

关 键 词：Fe-Cr-W-B合金 硼化物 力学性能 微观结构 热处理 

分 类 号：TG166.5[金属学及工艺—热处理]