Phase tranfor mations during rapid

مقدم أطروحة جامعية

Subhi, Aqil Zahir

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الإنتاج و المعادن

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2004

الملخص الإنجليزي

Rapid solidification has been attracted many investigators to study its effect on material properties.

Laser cladding, is considered to be one of the most important process of rapid solidification that gives desirable metallurgical, mechanical, tribological and chemical properties.

The importance of laser cladding is related to develop clad layers that have chemical compositions differ to the chemical composition of the substrate with minimum controlled dilution, In this study, continuous wave CO, laser with 1.7 and 2 kW were used to deposit clad layers of premixed powders of either Ni-I0 %A1 or Ni-30 % A1 onto Inconel 617 substrate.

Different cladding speeds were used ranging from 1 to 35 mm / s for premixed clad powder of Ni-10 % A1 and 1.65 to 11.2 mm / s for premixed clad powder of Ni-30 % A1 with 5 mm beam diameter.

Two feeding rates were used, 10 and 8.9 gm.

/ min for premixed clad powders of Ni-10 % A1 and Ni-30 % A1 respectively.

The other laser independent variables were selected to be constant.

The results showed that different mechanisms of growth were taken The Se Planar cellular / dendritic and dendritic growth.

volume fraction of growth region was different for each clad layer egion.

Different sizes of porosities and cracks were observed in the clad which the mechanism of porosities and cracks formation was percentages of area dilution were found ranging from 3.7 W§jg3% for premixed clad powder of Ni-10 %A1 and 6.88 to 41.02 % for clad powder of Ni-30 %A1 depending on the used laser padding independent variables.

Furthermore, dilution had vital role on inicrohardness values of clad layers.

Two clad layers have been chosen tobe with optimum properties.

These are clad layers of 3.9 and 3.2 mm / s cladding speeds that corresponding to premixed clad powders of jsji-10 %A1 and Ni-3 0 % A1 respectively.

التخصصات الرئيسية

الفيزياء

الموضوعات

• التطبيقات الصناعية
• الليزر

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305827