摘要
采用电子束选区熔化成形技术制备不同尺寸(Ф8 mm×25 mm,Ф25 mm×8 mm)TC4合金试样,研究了2种试样在粉末堆积方向的显微组织及硬度变化。结果表明:尺寸Ф8 mm×25 mm试样的显微组织主要由原始β柱状晶界处的针状α集束组织和晶内针状α相互相交错形成的网篮状魏氏组织组成,原始β柱状晶主轴平行于堆积方向并且贯穿各熔合层,残余β相弥散分布在α相基体中;尺寸Ф25 mm×8 mm试样顶部组织由针状α′相组成,中部组织中α′相受热分解为α相和β相,α相宽度较大,底部组织中条状α相贯穿原始β晶粒形成集束,残余β相在α相基体中呈连续网状分布。具有较大长宽比针状α相或α′相部位的显微硬度比具有较小长宽比条状和片状α相或α′相的硬度高。
The TC4 alloy samples with different dimension(Ф8 mm×25 mm,Ф25 mm×8 mm)were fabricated by electron beam selective melting forming technique.The evolution of microstructure and hardness along the powder deposition direction was studied.The results show that the microstructure of the sample with dimension ofФ8 mm×25 mm was composed of acicularαclusters at priorβcolumnar grain boundaries and net-basket-shaped widmanstatten structures formed by interlaced acicularαphase in grains.The axis of priorβcolumnar grains was parallel to the direction of powder deposition and grew through every deposition layer.The residualβphase dispersed amongαphase matrix.The top microstructure of the sample with dimension ofФ25 mm×8 mm consisted of acicularα′phases.The acicularα′phase in the middle microstructure was decomposed intoαphase andβphase,and the width ofαphase was relatively large.The stripαphase in the bottom microstucture grew through priorβgrains to form clusters.The residualβphase dispersed in the continuous network amongαphase matrix.The microhardness of the part with acicularαorα′phase of large length-width ratios was higher than that with strip and lamellarαorα′phase of small length-width ratios.
作者
童邵辉
李东
梁孟强
丁婷
冷星环
TONG Shaohui;LI Dong;LIANG Mengqiang;DING Ting;LENG Xinghuan(The Engineering Training Center,Shanghai University of Engineering Science,Shanghai 201620,China;School of Materials Engineering,Shanghai University of Engineering Science,Shanghai 201620,China)
出处
《机械工程材料》
CAS
CSCD
北大核心
2022年第2期43-47,共5页
Materials For Mechanical Engineering
基金
国家自然科学基金资助项目(51605276)。
关键词
电子束选区熔化
TC4钛合金
显微组织
显微硬度
electron beam selective melting
TC4 titanium alloy
microstructure
microhardness
