Powder Metallurgy

 Which of the following is the application of powder metallurgy?

• create unique materials with specific qualities that are impossible to accomplish using melting or shaping

• create unique materials with specific qualities that are possible to accomplish using melting or shaping

• All of the mentioned

• None of the mentioned

 Which of the following is a step of powder metallurgy?

• The production of metal powder

• The consolidation and fusing of the powder into a solid metal

• The compaction and shaping of the powder

• All of the mentioned

 For a given weight of metallic powders, the total surface area of the powders is increased by which of the following (two best answers):

• larger particle size

• smaller particle size

• higher shape factor

• smaller shape factor

 Which of the following powder shapes would tend to have the lowest interparticle friction?

• spherical

• acicular

• cubic

• flakey

• rounded

 Which of the following most closely typifies the sintering temperatures in PM?

where Tm = melting temperature of the metal

• 0.3 Tm

• 0.5 Tm

• 0.8 Tm

• Tm

Answer explanation

Sintering usually carried out at 70% to 90% of the metal's melting point (absolute scale)

 What is powder sintering process?

• Cold treatment used to improve a material’s strength and structural integrity

• Metal freezed to improve its strength and structural integrity

• Thermal treatment used to improve a material’s strength and structural integrity

• None of the mentioned

Answer explanation

Sintering is a thermal treatment that is widely used to improve a material’s strength and structural integrity.

 Impregnation refers to which of the following (two best answers)?

• filling the pores of the PM part with a molten metal

• putting polymers into the pores of a PM part

• oaking oil by capillary action into the pores of a PM part

• something that should not happen in a factory

 Which of the following are the essential parts of a sintering furnace?

• Burn-off zone, sintering zone, and cooling zone

• Sintering zone and cooling zone

• Preheat zone and sintering zone

Answer explanation

 (1) a burn-off zone or preheat zone for the removal of lubricants,
(2) a controlled high-temperature sintering zone, and
(3) a cooling and discharging zone.

 Which of the following are major components of atomization set-up?

• Melting, atomization chamber, collection tank

• Melting and superheating facility

• Melting, atomization chamber, dry collection

• Melting, atomization chamber

Answer explanation

The major components of a typical atomization set-up include: (1) Melting and superheating facility, (2) Atomization chamber, and (3) Powder collection tank which is further of two types- dry collection and wet collection

  _______ is a post sintering operation used to correct the dimensional defects during sintering.

• Joining

• Infiltration

• Sizing

• Impregnation