Martensitic Transformation Crystallography Calculation Of Titanium Alloy

Martensitic transformation crystallography,which is the core of the theory of Martensite phase transformation,is a subject which describes the crystallographic orientation relationship between parent phase and martensite and the crystal structure changes during the phase transition.Based on the crystallography and martensitic transformation basics,this paper studies the Bowles-Mackenzie representation theory(BM theory)and improves the calculating method of BM theory.The optimized BM theory can simplify the computing process,strengthen the logic of operation and accelerate the speed of operation.The crystallographic parameters in the martensitic transformation of B2-B19’in Ti-49.8Ni alloy<011>_M typeⅡtwin and{111}_Mtype I twin are calculated completely by the optimized BM theory.The crystallographic parameters in the martensitic transformation of B2-B19’in Ti-49.8Ni alloy<011>_M typeⅡtwin are calculated completely by the optimized BM theory.As a result,The Type II twin martensitic habit plane is very close to experimental data of Matsumoto,with a deviation of only 3.2°.The Strain matrix,the shear direction,the macroscopic deformation and the orientation before and after martensitic transformation are also in satisfactory agreement with the available experimental results.Combined with the BM theory,the volume before and after martensitic transformation is also discussed,the results show that volume slightly reduces after the phase change.The crystallographic parameters in the martensitic transformation of B2-B19’in Ti-49.8Ni alloy{111}_Mtype I twin are calculated completely by the optimized BM theory.As a result,The Type II twin martensitic habit plane is very close to the data calculated by WLR theory.The Strain matrix,the shear direction,the macroscopic deformation and the orientation before and after martensitic transformation are also in satisfactory agreement with the data calculated by WLR theory.Combined with the BM theory,the volume before and after martensitic transformation is also discussed,the results show that volume slightly reduces after the phase change.