CWB LEVEL 3 MODULE 24 (BASIC METALLURGY AND
WELDING METALLURGY OF ALUMINUM) EXAM|UPDATED
2025\26
Terms in this set (204)
What is the cause for weld bead Hot shortness of Al
cracking in Al ?
1.low density
2.Corrosion resistance
3.High electrical resistance
What are the properties of Al ?
4. High thermal conductivity
5.good appearance
6.toughness at low temps
True / False ? True
Al is covered with a coherent
oxide.
Thermal conductivity of Al is 4
______times that of Steel
Melting point of Al is about _______ half
of Steel
,Coefficient of thermal expansion twice
for Al is about______that of Steel
Modulus of elasticity (stiffness) one-third
for Al is about______that of Steel
True / False True
"Nitrogen is not inert to Al and is
not used for sheilding"
What is responsible for Al's Al oxide but it changes to Magnesium oxide (MgO) or
excellent corrosion resistance? Magnesium spinel ( Mg Al2O4) when the Mg % exceeds 0.05%.
What is the thickness of Al oxide 50-150 angstroms
on the surface of Al ?
True/ False ? True
The form of magnesium oxide is
a function of the magnesium
concentration and the thermal
history of the alloy
True / False ? True
The oxide transformation from
aluminum oxide to magnesium
oxide or magnesium spinel ,has
a profound effect on the solid
- state bonding b/w any clad
and the Al base
, The solid -state bonding b/w Al Less than 0.05%
and another metal or another
Aluminum alloy generally
requires a control of the
magnesium level to____%
Why does Mg has the profound 1. Mg has a greater affinity than Al for O2.
influence on the oxide found on 2.Mg behaves as a surface-active element in Al, that is, it
Al? tends to diffuse readily to the surface of the metal.
The oxidation rate of Mg greater
containing alloys is _____________ than
for Mg free alloys.
Why is oxide thickness on an The oxidation rate of Mg containing alloys is greater than for Mg
Mg- Al alloy surface thicker than free alloys.
one on a Mg free alloy for
the same thermal /
mechanical
history?
Which is the element which Lithium
reacts with Mg oxide to form its
oxides on the Al surface?
Which is the surface oxide for Lithium oxide / spinel
lithium bearing Al alloys?
WELDING METALLURGY OF ALUMINUM) EXAM|UPDATED
2025\26
Terms in this set (204)
What is the cause for weld bead Hot shortness of Al
cracking in Al ?
1.low density
2.Corrosion resistance
3.High electrical resistance
What are the properties of Al ?
4. High thermal conductivity
5.good appearance
6.toughness at low temps
True / False ? True
Al is covered with a coherent
oxide.
Thermal conductivity of Al is 4
______times that of Steel
Melting point of Al is about _______ half
of Steel
,Coefficient of thermal expansion twice
for Al is about______that of Steel
Modulus of elasticity (stiffness) one-third
for Al is about______that of Steel
True / False True
"Nitrogen is not inert to Al and is
not used for sheilding"
What is responsible for Al's Al oxide but it changes to Magnesium oxide (MgO) or
excellent corrosion resistance? Magnesium spinel ( Mg Al2O4) when the Mg % exceeds 0.05%.
What is the thickness of Al oxide 50-150 angstroms
on the surface of Al ?
True/ False ? True
The form of magnesium oxide is
a function of the magnesium
concentration and the thermal
history of the alloy
True / False ? True
The oxide transformation from
aluminum oxide to magnesium
oxide or magnesium spinel ,has
a profound effect on the solid
- state bonding b/w any clad
and the Al base
, The solid -state bonding b/w Al Less than 0.05%
and another metal or another
Aluminum alloy generally
requires a control of the
magnesium level to____%
Why does Mg has the profound 1. Mg has a greater affinity than Al for O2.
influence on the oxide found on 2.Mg behaves as a surface-active element in Al, that is, it
Al? tends to diffuse readily to the surface of the metal.
The oxidation rate of Mg greater
containing alloys is _____________ than
for Mg free alloys.
Why is oxide thickness on an The oxidation rate of Mg containing alloys is greater than for Mg
Mg- Al alloy surface thicker than free alloys.
one on a Mg free alloy for
the same thermal /
mechanical
history?
Which is the element which Lithium
reacts with Mg oxide to form its
oxides on the Al surface?
Which is the surface oxide for Lithium oxide / spinel
lithium bearing Al alloys?
