Lin GENG
,
Jie ZHANG
,
C.Bartels
,
G. Gottstein
材料科学技术（英文）
Hardness of the TiB2/7075 composite increased with increasing deformation temperature. In the annealed TiB2/7075 composite, a great amount of fiber-like MgZn2 phases (about 1 mum in length) and small MgZn2 phases (about 100 nm in size) were precipitated nearby the grain boundaries where the TiB2 particles exist. After deformation at 300℃, some of the large precipitates and all the small precipitates in these area dissolved into the matrix, meanwhile, fine precipitates were formed in grains. After deformation at 450℃, all the precipitates in the annealed composite dissolved into the matrix, and new phases were precipitated in grains. The dissolution of the large fiber-like precipitate makes the saturation level of the matrix increased and leads to an increased solution hardening and natural aging, which contribute much to the hardening effect.
关键词:
M.Naka
,
Jie ZHANG
,
Yu ZHOU
材料科学技术（英文）
Si3N4 ceramic was jointed to itself using a filler alloy of Cu76.5Pd8.5Ti15, and the mechanical properties of the joint were measured and analyzed. By using a filler alloy of Cu76.5Pd8.5Ti15, the Si3N4/ Si3N4 joints were obtained by brazing at 1373～1473 K for 0.9～5.4 ks under a pressure of 2×10-3 MPa. The effect of brazing parameters on the shear strength of the joint was investigated. When the brazing temperature and holding time is 1423 K and 5.4 ks respectively, the maximum shear strength of the Si3N4/Si3N4 joint is obtained to be 198 MPa.
关键词:
Si3N4 ceramic
,
null
,
null
,
null
