The solidification cooling curve of Al-6.5 Mg-0.14 Ti-0.12 Zr is distributed according with the Logarithm function

which presents as paste solidification easily due to the temperature interval of 111.4℃.The investment mold obtains the highest cooling rate

which is higher than the resin sand and plaster mold.Absence of casting/mold interface reaction can be observed during the solidification process

and the alloy has excellent filling capability

which can fill completely the different molds.The as-cast microstructure of the alloy is composed ofα-Al phase and Al

3

Mg

2

phase

and the Al

3

Mg

2

phase is distributed uniformly along the grain boundary.The average size ofα-Al phase can be reduced from 324μm to 132μm in resin casting compared with that of ones in plaster mold casting.The average tensile strength

yield strength

elongation and Vickers hardness of investment casting samples reach up to 274.7 MPa、136 MPa、14.9% and 60 HV

respectively.After the solid solution treatment at 400℃for 12 h

the average tensile strength

yield strength

elongation and Vickers hardness of the investment casting samples are increased to 322.7 MPa、144 MPa、31.9% and 68.3 HV

respectively.The as-cast fracture is presented absolutely crystal fracture

and some micro-dimples can be observed.The rupture mode is changed to dimple fracture after the solution treatment

and small Al

3

Mg

2

phase

Al

3

Ti phase and Al

3

Zr phase particles are generated in the dimple.