Ti-6.5Al-2.5Sn-9Zr-0.5Mo-0.25Si-1Nb-1W-0.1Er-xB　(x　=　0,　0.1,　0.2,　0.4,　0.6　and　0.8　wt%)　with　different　boron　contents　are　fabricated　for　investigation.　Influences　of　boron　element　and　its　amounts　on　phase　constitutions,　microstructures,　textures　and　compression　mechanical　properties　are　carefully　studied.　With　the　increasing　boron　additions,　contents　of　TiB　phase　increase,　and　the　maximum　intensities　of　textures　decrease.　Microstructures　are　significantly　and　continuously　refined　after　adding　boron　element　and　with　the　increasing　boron　additions,　and　turning　point　of　refinement　rates　for　different　microstructural　parameters　is　found　at　0.2　wt%　boron　content.　Strengths　increase　monotonously,　while　elongations　increase　firstly　and　decrease　afterwards.　The　maximum　value　of　elongation　is　acquired　at　boron　content　of　0.2　wt%.　On　the　premise　of　ensuring　plasticity,　0.2　wt%　boron　content　is　the　most　appropriate　amount　for　microstructural　refinement　and　mechanical　properties　enhancement　for　current　near　alpha　titanium　alloys.　Meanwhile,　aspect　ratios　of　TiB　whiskers　increase　with　the　increasing　boron　contents.　Lots　of　near　equiaxed　alpha　grains　or　alpha　grains　with　irregular　morphologies　are　discovered　around　TiB　phase.　Distorted　and　twisted　alpha　grain　boundaries　are　also　obviously　detected　in　boron　containing　alloys.　Moreover,　premature　fracture　of　alloys　containing　TiB　whiskers　is　largely　influenced　by　the　fracture　of　these　brittle　reinforcements.　(C)　2021　Published　by　Elsevier　Ltd　on　behalf　of　The　editorial　office　of　Journal　of　Materials　Science　&　Technology.