In this work, the effects of mould pre-heating temperatures and hot isostatic pressing （HIPping） process on the microstructural characteristics and mechanical properties, including static tensile and damage- toleran...In this work, the effects of mould pre-heating temperatures and hot isostatic pressing （HIPping） process on the microstructural characteristics and mechanical properties, including static tensile and damage- tolerance properties of large thin-wall cylindrical Ti-6Al-4V casting, have been studied. The experimental results show that with the increasing mould pre-heating temperature from 673 to 873 K, the casting mi- crostructures change from a mixture of Widmanstatten and colony microstructure to a primary colony. The centre of the thick wall section has relatively coarse microstructure than the edge and thin section. Lower mould pre-heating temperature brings about more porosities. HIPping process, which not only reduces the casting pores effectively but also increases the prior β grain boundary cohesion and coars- ens the microstructure, is essential to improving the ductility of the casting. Due to the oxygen contamination and finer microstructure on the surface, micro-hardness profiles on the cross section present a decreas- ing tendency from the surface to inner. The thickness of the reaction layers for the different mould pre-heating temperatures is nearly the same （-450 μm）. On the whole, the tensile strength and micro- hardness decrease with increasing mould pre-heating temperature from 673 to 873 K. However, the fracture toughness and fatigue crack growth resistance of the castings increase with increasing mould pre- heating temperature.展开更多
Like other Asian countries,property prices in China have rebounded sharply since the beginning of this year,fueled by loose monetary policies and aggressive bank lending.
The paper studies an often-observed phenomenon of diversification of manufacturing firms into real estate development in East Asian economies. Utilizing a sudden change in China＇s accounting standards that requires f...The paper studies an often-observed phenomenon of diversification of manufacturing firms into real estate development in East Asian economies. Utilizing a sudden change in China＇s accounting standards that requires firms to disclose information about their real estate holdings for investment purpose （or investment property）, we examine both the impact of such diversification on firms＇ investment in their original business and the stock market response to such diversification. Our results confirm there exists underinvestment in original business （or hollowing out of the real economy） for firms diversifying into real estate, and that there is a lack of investor response to such diversification, in both short-rim and long-run. Our study calls for further research on the role of real estate development in the long-run competitiveness of developing economies.展开更多
基金financial support from the COLTS programme (Programme No. FP7-AAT-2010-RTD-CHINA)
文摘In this work, the effects of mould pre-heating temperatures and hot isostatic pressing （HIPping） process on the microstructural characteristics and mechanical properties, including static tensile and damage- tolerance properties of large thin-wall cylindrical Ti-6Al-4V casting, have been studied. The experimental results show that with the increasing mould pre-heating temperature from 673 to 873 K, the casting mi- crostructures change from a mixture of Widmanstatten and colony microstructure to a primary colony. The centre of the thick wall section has relatively coarse microstructure than the edge and thin section. Lower mould pre-heating temperature brings about more porosities. HIPping process, which not only reduces the casting pores effectively but also increases the prior β grain boundary cohesion and coars- ens the microstructure, is essential to improving the ductility of the casting. Due to the oxygen contamination and finer microstructure on the surface, micro-hardness profiles on the cross section present a decreas- ing tendency from the surface to inner. The thickness of the reaction layers for the different mould pre-heating temperatures is nearly the same （-450 μm）. On the whole, the tensile strength and micro- hardness decrease with increasing mould pre-heating temperature from 673 to 873 K. However, the fracture toughness and fatigue crack growth resistance of the castings increase with increasing mould pre- heating temperature.
文摘Like other Asian countries,property prices in China have rebounded sharply since the beginning of this year,fueled by loose monetary policies and aggressive bank lending.
文摘The paper studies an often-observed phenomenon of diversification of manufacturing firms into real estate development in East Asian economies. Utilizing a sudden change in China＇s accounting standards that requires firms to disclose information about their real estate holdings for investment purpose （or investment property）, we examine both the impact of such diversification on firms＇ investment in their original business and the stock market response to such diversification. Our results confirm there exists underinvestment in original business （or hollowing out of the real economy） for firms diversifying into real estate, and that there is a lack of investor response to such diversification, in both short-rim and long-run. Our study calls for further research on the role of real estate development in the long-run competitiveness of developing economies.
