The TiB

2 p

reinforced Fe-Cr matrix composites were prepared by in-situ synthesis method. The microstructure and high temperature oxidation behavior of both the composites were analyzed by X-ray diffraction（XRD）

scanning electron microscopy（SEM） and energy dispersive spectrometer（EDS）. The results indicate that excessive Ti（6%） can effectively eliminate（Fe

Cr）

2

B mesophases

and the morphology of TiB

2

particles is converted from petal to regular polygon

where the microhardness is increased greatly from 400 HV

0.5

to 860 HV

0.5

and the fracture toughness is enhanced from 2.91 MPa·m

1/2

to 5.47 MPa·m

1/2

. However

the interface between coarse primary TiB

2

particles and matrix provide oxygen diffusion channel and the original two-layer structure of oxide layer（rutile TiO

2

outer layer+compact Cr

2

O

3

inner layer） is transformed into three-layer structure（rutile TiO

2

outer layer+compact Cr

2

O

3

transition layer+TiO

2

inner layer）

resulting in a significant decrease in oxidation resistance at 900 ℃

where the oxidation gain rate is increased by 307.4%.